Efficient synthesis of aryl-substituted carbazoles via tandem double or triple suzuki coupling and cadogan cyclization

Tetrahedron 73 (2017) 1413e1423

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Efficient synthesis of aryl-substituted carbazoles via tandem double or triple suzuki coupling and cadogan cyclization Hyeong Seok Kim, Deuk-young Goo, Sang Kook Woo* Department of Chemistry, University of Ulsan, 93 Daehak-Ro, Nam-Gu, Ulsan 44610, South Korea

a r t i c l e i n f o

a b s t r a c t

Article history: Received 24 December 2016 Received in revised form 11 January 2017 Accepted 17 January 2017 Available online 25 January 2017

An efficient one-step method to prepare aryl-substituted carbazoles via tandem double or triple CeC bond formations by multiple Suzuki couplings and CeN bond formation by Cadogan cyclization has been developed. The developed method employs commercially available or easily preparable polybromonitrobenzenes and arylboronic acids as starting materials, tolerates various functional groups, and provides good yields. © 2017 Elsevier Ltd. All rights reserved.

Keywords: Aryl-substituted carbazole Tandem reaction Cadgan cyclization Suzuki coupling One-pot reaction

1. Introduction The carbazole structure is an important motif found in many bioactive natural products and pharmaceuticals,1 as well as functional organic materials,2 and many methods have been developed for its preparation.3 In particular, aryl-substituted carbazoles comprise the important core structure of various biologically and pharmaceutically active molecules including hyellazole, 6chlorohyellazole,4 and Wee1 and Chk1 inhibitors5 (Fig. 1). In addition, aryl-substituted carbazoles serve as building blocks for many organic functional materials.6 Because of their importance, there are many known methods for the synthesis of aryl-substituted carbazoles. In general, these structures are prepared by multi-step processes from simple starting materials: (1) synthesis of the carbazole core structure by various methods, (2) halogenation of carbazole, and (3) arylation of halogenated carbazoles by transition metal-mediated crosscoupling (Scheme 1).7 Although numerous synthetic approaches to aryl-substituted carbazoles have been reported, improvement is still needed to provide a step economic, regioselective, and mild method. More recently, direct synthesis of aryl-substituted carbazoles

have been reported.8 Li reported an acid-catalyzed benzannulation of indoles with g-carbonyl tert-butylperoxides.8a Lee reported a cesium carbonate-mediated condensation of 2-nitrochalcones or 2nitrocinnamaldehydes with various b-ketoesters or 1,3-diaryl-2propanones.8b Verma reported the palladium-catalyzed CeH activation of styrylindoles or styrene-substituted indoles with styrenes or acrylates.8c Recently, we reported a one-pot synthetic method for carbazoles that featured cascade carbon-carbon/carbon-nitrogen bond formations via Suzuki cross-coupling and Cadogan cyclization.9 The Suzuki cross-coupling reaction is one of the most important methods for carbon-carbon bond formation.10 Recently, double or triple Suzuki cross-coupling reactions have been devised.11 These methods can be used to easily prepare various multiple vinyl or aryl-substituted compounds. Therefore, we envisioned a tandem double or triple Suzuki cross-coupling and reductive amination as a step economic method to prepare aryl-substituted carbazoles. Herein, we present a highly efficient one-step synthesis of arylsubstituted carbazoles using tandem double or triple CeC bond formations by multiple Suzuki reactions and CeN bond formation by Cadogan cyclization12 (Scheme 1). 2. Results and discussion

* Corresponding author. E-mail address: [email protected] (S.K. Woo). http://dx.doi.org/10.1016/j.tet.2017.01.038 0040-4020/© 2017 Elsevier Ltd. All rights reserved.

In initial experiments, we chose the tandem reaction of 2,4dibromonitrobenzene 1a and phenylboronic acid 2a to form 2-

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Fig. 1. Selected examples of aryl-substituted carbazoles.

Scheme 1. Approaches to the Synthesis of Aryl-substituted Carbazoles.

phenyl-9H-carbazole 3aa. Treatment of 2,4-dibromonitrobenzene 1a (100 mol%) with phenylboronic acid 2a (200 mol%) in the presence of palladium acetate (2 mol%) and PPh3 (250 mol%) in oDCB at 180
C for 24 h gave the desired 2-phenyl-9H-carbazole 3aa in 31% yield. The yield slightly improved to 38% when the amount of phenylboronic acid 2a was increased from 2.0 to 2.6 equivalents (Table 1, entry 3). Further increases in yield were obtained by increasing the amount of PPh3, catalyst loading, and reaction time (Table 1, entries 4e6). Examination of the solvent concentration

Table 1 Optimization of the reaction conditionsa.

revealed that o-DCB 0.2 M was optimal for this reaction (Table 1, entry 10). After optimization of the reaction conditions, we next examined coupling reactions of various polybromonitrobenzenes 1 with phenylboronic acid 2a to generate various aryl-substituted carbazoles (Table 2). It was found that the position of bromine substitution in the nitrobenzene was very important. 2,4-Dibromo-1nitrobenzene 1b gave similar results to 1,4-dibromo-2nitrobenzene 1a, but 1,2-dibromo-3-nitrobenzene 1c and 1,3dibromo-2-nitrobenzene 1d gave the corresponding carbazoles 3ca and 3da in low yields because of steric hinderance in the Cadogan cyclization. 1,2,4-Tribromo-5-nitrobenzene 1e also smoothly underwent the reaction with modified reaction conditions, providing the corresponding diphenyl-substituted carbazole 3ea in good yield. However, 1,2,3,4-tetrabromo-5-nitrobenzene only produced a trace amount of product. Therefore, we continued to survey the substrate scope of the tandem reaction with 1a, 1b, and 1e. Based on the optimized reaction conditions, we focused our attention on the substrate scope. First, the scope of arylboronic acids 2 in the reaction was examined, as illustrated in Table 3. 1,4Dibromo-2-nitrobenzene 1a and 2,4-dibromo-1-nitrobenzene 1b were coupled to a diverse range of arylboronic acids 2 to form the corresponding aryl-substituted carbazoles 3 in good to excellent yields. Notably, arylboronic acids 2 bearing either electronwithdrawing or electron-donating groups, such as alkyl, methoxy, and halogen substituents, at the ortho or para-position smoothly underwent the tandem reactions to afford the desired products (3ab-ac, 3ae-af, 3ah-ai, 3bb, 3be, and 3bi) in 62e93% yield. Additionally, sterically bulky-substituted arylboronic acid 2c gave the corresponding products 3ac in 87% yield, respectively. The method also proceeded well for reactions of 1a with 2,4- or 2,5disubstituted arylboronic acids (2j-l) performed under the standard reaction conditions, providing the desired products (3aj-al) in 87e96% yield. The coupling reactions of 1,4-dibromo-2nitrobenzene 1a with 1-naphthylboronic acid 2m and 4-methyl1-naphthylboronic acid 2n affored the desired products 3am and 3an in 96% and 94% yield, respectively. Remarkably, trisubustituted arylboronic acids (2o, 2p) worked well to provide the corresponding products 3ao and 3ap in 76% yield.

H.S. Kim et al. / Tetrahedron 73 (2017) 1413e1423

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Table 2 Polybromonitrobenzene conversion to aryl-substituted carbazolesa.3

Table 3 Substrate scope of various aryl boronic acidsa.4

Next, we turned our attention to the coupling of phenylboronic acid 2a with a broad range of substituted 1,4-dibromo-2nitrobenzenes (1g-j) and 2,4-dibromo-1-nitrobenzenes (1k-m)

(Table 4). Under the optimized reaction conditions, various dibromonitrobenzenes (1g-o) containing electron-rich or electrondeficient functional groups were reacted with phenylboronic acid

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Table 4 Substrate scope with various dibromonitrobenzenesa.5

Table 5 Substrate scope of various dibromonitrobenzenes with aryl boronic acidsa.6

2a to afford the corresponding aryl-substituted carbazoles in good yields (3ga-ma: 52e95% yield). By increasing the catalyst loading of Pd(OAc)2e10 mol%, the reaction of ester substituted 1,4-dibromo2-nitrobenzenes 1j with phenylboronic acid 2a gave the corresponding product 3ja in 52% yield, respectively (see Table 4). We further extended the scope of the reaction using substituted 1,4-dibromo-2-nitrobenzenes (1g-j) and 2,4-dibromo-1nitrobenzenes (1k-m) with various arylboronic acids 2 under the optimized conditions (Table 5). The reactions of substituted 1,4dibromo-2-nitrobenzenes (1g-j) with ortho- or para-substituted arylboronic acids (2b-2i) containing electron-rich or electron-

deficient functional groups provided the corresponding carbazoles in good yields. Treatment of the 1,4-dibromo-2-methyl-5nitrobenzene 1g with disubstituted arylboronic acids 2l provided the products 3gl in 91% yield, respectively. A one-pot reaction of substituted 1,4-dibromo-2-nitrobenzenes (1g-i) with 1naphthylboronic acid 2m and 4-methyl-1-naphthylboronic acid 2n gave the desired products (3gm, 3hn, 3in) in excellent yields. Similarly, reactions of substituted 2,4-dibromo-1-nitrobenzenes (1k-m) with mono-, di-, and tri-substituted arylboronic acids (2bd, 2f-g, 2j, and 2p) gave the corresponding carbazoles in good yields.

H.S. Kim et al. / Tetrahedron 73 (2017) 1413e1423

Not only dibromonitrobenzenes, but also tribromonitrobenzenes were amenable to the developed method (Scheme 2). Under modified reaction conditions, the coupling of 1,2,4-tribromo5-nitrobenzene 1e with para-substituted arylboronic acids (2b, and 2f) containing methyl and halogen groups afforded the corresponding diaryl-substituted carbazoles in good yields (3eb, and 3ef: 60e70% yield). Based on the reported literature for Suzuki cross-couplings10d and Cadogan cyclizations,13 a plausible mechanism for the tandem reaction is depicted in Scheme 3. Biaryl intermediate I is prepared via well-established palladium-catalyzed double Suzuki cross-coupling of 1a with 2a. Next, the nitro group of biaryl intermediate I can be converted to nitroso aryl intermediate III by addition of PPh3 to the nitro oxygen, followed by elimination of triphenylphosphine oxide. Zwitterion IV, formed by addition of PPh3 to the nitroso group in III, is subsequently converted to nitrene V13b by elimination of triphenylphosphine oxide. Intramolecular cyclization of the nitrene generates isocarbazole VI that could also result from direct cyclization of zwitterion IV.12c Finally, isocarbazole VI is converted to the desired carbazole 3aa via a 1,5hydrogen shift.13d 3. Conclusions In conclusion, we demonstrated a highly efficient method to synthesize aryl-substituted carbazoles via cascade double or triple Suzuki cross-coupling and Cadogan cyclization. This method employs commercially available or easily preparable polybromonitrobenzenes (1a-m) and arylboronic acids (2a-p) as starting materials and tolerates substrates that contain a variety of electron-neutral, -rich, or -deficient functional groups. Further application of this strategy to the synthesis of natural products and other heterocycles is currently underway. 4. Experimental section 4.1. General information All reactions were run under an atmosphere of air under anhydrous conditions unless otherwise indicated. Dichloromethane (CH2Cl2), tetrahydrofuran (THF), dimethylformamide (DMF) and toluene (PhMe) were obtained from Pure-Solv MD-5 Solvent Purification System (Innovative Technology). Pressure tubes (13  100 mm, PYREXPLUS) were dried in oven for overnight and cooled under a stream of nitrogen prior to use. All commercial reagents were used directly without further purification. The progress of reaction was checked on TLC plates (Merck 5554 Kiesel gel 60 F254). Column chromatography was performed on silica gel (Merck 9385 Kiesel gel 60) using hexanes-EtOAc (v/v) or hexanesacetone (v/v). Infrared spectra were recorded on a Shimadzu (Raffinity-1S). High-resolution mass spectra (EI) were obtained on a Jeol JMS700 HRMS at the Korea Basic Science Center(KBSI), Daegu, Korea. Accurate masses are reported for the molecular ion [Mþ]. Nuclear magnetic resonance spectra (1H NMR and 13C NMR) were

Scheme 2. Reaction of tribromonitrobenzenes with aryl boronic acidsa. aReaction conditions: 1a (0.25 mmol), 2a (0.975 mmol), catalyst (7.5 mol%), PPh3 (500 mol%), K2CO3 (600 mol%), o-DCB (0.1 M) under air in a pressure tube).

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Scheme 3. Proposed mechanism for the synthesis of 2-phenyl-9H-carbozole 3aa.

recorded with a Bruker (300 MHz) spectrometer. Chemical shift values were recorded as parts per million relative to tetramethylsilane as an internal standard unless otherwise indicated, and coupling constants in Hertz. The following abbreviations are used: m (multiplet), s (singlet), d (doublet), t (triplet), q (quartet), dd (doublet of doublets), etc. 4.1.1. General procedure A for aryl-substituted carbazole synthesis To a re-sealable pressure tube (13  100 mm) equipped with magnetic stir bar were added o-bromonitrobenzene 1 (0.25 mmol, 100 mol%), aryl boronic acid 2 (0.65 mmol, 260 mol%), Pd(OAc)2 (0.0125 mmol, 5 mol%), PPh3 (1.25 mmol, 500 mol %), K2CO3 (1 mmol, 400 mol%) and o-DCB (1.25 mL, 0.2 M concentration with respect to o-bromonitrobenzene 1. The mixture was heated at 180
C (oil bath temperature) for 48 h, at which point the reaction mixture was allowed to cool to ambient temperature. The reaction mixture was filtered through a pad of celite and the resulting liquor was concentrated in vacuo and purified by flash column chromatography (SiO2) under the conditions noted to furnish the corresponding product. 4.1.1.1. 2-Phenyl-9H-carbazole (3aa). 9Following the general procedure A, 3aa was obtained as a white solid (50 mg, 83% yield). Mp 220e222
C; Rf ¼ 0.36 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 11.33 (s, 1H), 8.18 (d, J ¼ 8.1 Hz, 1H), 8.13 (d, J ¼ 7.7 Hz, 1H), 7.80e7.67 (m, 3H), 7.54e7.33 (m, 6H), 7.17 (t, J ¼ 7.4 Hz, 1H); 13C NMR (75 MHz, DMSO) d 141.26, 140.43, 140.35, 137.88, 128.99, 127.12, 127.06, 125.70, 122.23, 121.88, 120.68, 120.32, 118.76, 117.89, 111.06, 108.93; FTIR (neat): y 3539, 2464, 1344, 1221 cm1; HRMS m/z (EI): calcd. For C18H13N [Mþ] 243.1048, found 243.1048. 4.1.1.2. 2-Methyl-7-(p-tolyl)-9H-carbazole (3ab). Following the general procedure A, 3ab was obtained as a white solid (63 mg, 93% yield). Mp 238e240
C; Rf ¼ 0.26 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 10.71 (s, 1H), 7.64 (d, J ¼ 8.1 Hz, 1H), 7.52 (d, J ¼ 7.9 Hz, 1H), 7.25e7.11 (m, 3H), 6.95 (dd, J ¼ 8.1, 0.9 Hz, 1H), 6.84 (d, J ¼ 8.0 Hz, 3H), 6.54 (d, J ¼ 7.9 Hz, 1H), 2.02 (s, 3H), 1.91 (s, 3H); 13 C NMR (75 MHz, DMSO) d 142.13, 141.80, 139.81, 138.66, 137.59, 136.47, 130.93, 128.17, 123.11, 121.62, 121.60, 121.39, 121.32, 118.93, 112.35, 109.87, 23.13, 22.08; FTIR (neat) y 3434, 2285, 1396, 1261, 1195 cm1; HRMS m/z (EI): calcd. For C20H17N [Mþ] 271.1361, found 271.1361.

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4.1.1.3. 2-(tert-butyl)-7-(4-(tert-butyl)Phenyl)-9H-carbazole (3ac). Following the general procedure A, 3ac was obtained as a White solid (77 mg, 87% yield). Mp 208e210
C; Rf ¼ 0.38 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.25 (s, 1H), 8.10 (d, J ¼ 8.1 Hz, 1H), 8.03 (d, J ¼ 8.3 Hz, 1H), 7.74 (d, J ¼ 1.4 Hz, 1H), 7.70e7.64 (m, 2H), 7.55 (d, J ¼ 1.7 Hz, 1H), 7.54e7.49 (m, 2H), 7.46 (dd, J ¼ 8.1, 1.6 Hz, 1H), 7.30 (dd, J ¼ 8.3, 1.7 Hz, 1H), 1.41 (s, J ¼ 6.6 Hz, 9H), 1.37 (s, J ¼ 14.3 Hz, 9H); 13C NMR (75 MHz, Acetone) d 150.51, 149.92, 141.89, 141.82, 140.00, 138.99, 127.65, 126.53, 123.15, 121.42, 120.95, 120.46, 118.93, 117.91, 109.61, 108.15, 35.60, 35.01, 32.08, 31.67; FTIR (neat) y 3413, 3182, 1362, 1256, 773 cm1; HRMS m/z (EI): calcd. For C26H29N [Mþ] 355.2300, found 355.2299. 4.1.1.4. 2-Chloro-7-(4-chlorophenyl)-9H-carbazole (3ae). Following the general procedure A, 3ae was obtained as a White solid (48 mg, 62% yield). Mp 251e253
C; Rf ¼ 0.46 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.60 (s, 1H), 8.19 (dd, J ¼ 8.2, 0.6 Hz, 1H), 8.13 (dd, 1H), 7.79 (dd, J ¼ 1.6, 0.6 Hz, 1H), 7.77e7.73 (m, 2H), 7.58e7.56 (m, 1H), 7.54e7.47 (m, 3H), 7.21 (dd, J ¼ 8.3, 1.9 Hz, 1H); 13C NMR (75 MHz, Acetone) d 141.25, 141.05, 140.49, 137.76, 132.64, 130.90, 128.83, 128.76, 122.08, 121.61, 121.36, 120.65, 119.35, 118.72, 110.82, 109.32; FTIR (neat) y 3287, 3107, 1819, 1245, 1167 cm1; HRMS m/z (EI): calcd. For C18H11Cl2N [Mþ] 311.0269, found 311.0266. 4.1.1.5. 2-Fluoro-7-(4-fluorophenyl)-9H-carbazole (3af). Following the general procedure A, 3af was obtained as a White solid (44 mg, 63% yield). Mp 244e246
C; Rf ¼ 0.35 (25% acetone/ hexanes); 1H NMR (300 MHz, CDCl3) d 8.14 (s, 1H), 8.05 (d, J ¼ 8.1 Hz, 1H), 7.99 (dd, J ¼ 8.6, 5.4 Hz, 1H), 7.67e7.60 (m, 2H), 7.56 (d, J ¼ 1.1 Hz, 1H), 7.43 (dd, J ¼ 8.1, 1.5 Hz, 1H), 7.20e7.10 (m, 3H), 7.03e6.94 (m, 1H); 13C NMR (75 MHz, DMSO) d 163.39, 162.90, 160.17, 159.73, 141.04, 140.97, 140.87, 137.62, 137.59, 136.58, 129.01, 128.90, 121.72, 121.57, 121.48, 120.51, 118.98, 118.30, 115.90, 115.62, 109.00, 106.95, 106.63, 97.68, 97.34; FTIR (neat) y 3234, 3161, 1253, 1162, 967 cm1; HRMS m/z (EI): calcd. For C18H11F2N [Mþ] 279.0860, found 279.0858. 4.1.1.6. 5-Methyl-2-(o-tolyl)-9H-carbazole (3ah). Following the general procedure A, 3ah was obtained as a White solid (62 mg, 91% yield). Mp 126e128
C; Rf ¼ 0.33 (25% acetone/hexanes); 1H NMR (300 MHz, CDCl3) d 8.19 (d, J ¼ 8.1 Hz, 1H), 8.12 (s, 1H), 7.39e7.38 (m, 1H), 7.37e7.27 (m, 6H), 7.22 (dd, J ¼ 8.1, 1.4 Hz, 1H), 7.04 (dd, J ¼ 4.1, 2.9 Hz, 1H), 2.91 (s, 3H), 2.33 (s, 3H); 13C NMR (75 MHz, CDCl3) d 142.62, 139.85, 139.48, 139.25, 135.71, 133.39, 130.45, 130.25, 127.25, 125.85, 125.74, 122.63, 122.08, 121.78, 121.12, 121.06, 111.07, 108.28, 20.91, 20.77; FTIR (neat) y 3178, 2326, 1532, 1317, 1269 cm1; HRMS m/z (EI): calcd. For C20H17N [Mþ] 271.1361, found 271.1360. 4.1.1.7. 5-Methoxy-2-(2-methoxyphenyl)-9H-carbazole (3ai). Following the general procedure A, 3ai was obtained as a White solid (68 mg, 90% yield). Mp 138e140
C; Rf ¼ 0.29 (25% acetone/ hexanes); 1H NMR (300 MHz, CDCl3) d 8.35 (d, J ¼ 8.1 Hz, 1H), 8.05 (s, 1H), 7.57 (s, 1H), 7.46e7.41 (m, 2H), 7.39e7.30 (m, 2H), 7.14e6.99 (m, 3H), 6.69 (d, J ¼ 8.0 Hz, 1H), 4.09 (s, 3H), 3.84 (s, 3H); 13C NMR (75 MHz, CDCl3) d 156.61, 156.29, 141.32, 138.70, 135.34, 131.57, 131.47, 128.42, 126.62, 122.47, 121.68, 120.94, 112.62, 111.35, 111.11, 103.60, 100.35, 55.72, 55.54; FTIR (neat) y 3266, 2824, 1771, 1366, 1178, 1011 cm1; HRMS m/z (EI): calcd. For C20H17NO2 [Mþ] 303.1259, found 303.1261. 4.1.1.8. 2-Fluoro-7-(4-fluoro-2-methylphenyl)-4-methyl-9H-carbazole (3aj). Following the general procedure A, 3aj was obtained as a White solid (74 mg, 96% yield). Mp 136e138
C; Rf ¼ 0.37 (25%

acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.66 (s, 1H), 8.11 (d, J ¼ 8.1 Hz, 1H), 7.46 (s, 1H), 7.28 (dd, J ¼ 8.3, 6.1 Hz, 1H), 7.12 (dd, J ¼ 8.2, 1.2 Hz, 2H), 7.08e6.95 (m, J ¼ 14.4, 9.3, 4.2 Hz, 2H), 6.80 (dd, 1H), 2.83 (s, 3H), 2.28 (s, 3H); 13C NMR (75 MHz, Acetone) d 164.25, 163.97, 161.02, 160.80, 141.98, 141.80, 141.48, 141.46, 139.68, 139.63, 138.84, 138.74, 138.34, 135.65, 135.51, 132.41, 132.29, 122.98, 122.28, 121.60, 118.83, 117.43, 117.15, 113.21, 112.93, 112.10, 109.13, 108.81, 95.80, 95.45, 20.84, 20.82, 20.74, 20.72; FTIR (neat) y 3156, 2838, 1374, 1264, 1174, 1045 cm1; HRMS m/z (EI): calcd. For C20H15F2N [Mþ] 307.1173, found 307.1174. 4.1.1.9. 7-(2,5-Dimethylphenyl)-1,4-dimethyl-9H-carbazole (3ak). Following the general procedure A, 3ak was obtained as a White solid (67 mg, 90% yield). Mp 136e138
C; Rf ¼ 0.39 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.39 (s, 1H), 8.18 (d, J ¼ 8.1 Hz, 1H), 7.47 (dd, J ¼ 1.5, 0.6 Hz, 1H), 7.21e7.05 (m, 5H), 6.90 (d, J ¼ 7.3 Hz, 1H), 2.84 (s, 3H), 2.55 (s, 3H), 2.34 (s, 3H), 2.26 (s, 3H); 13 C NMR (75 MHz, Acetone) d 143.50, 140.99, 140.51, 139.75, 135.72, 132.87, 131.46, 131.07, 130.94, 128.48, 126.78, 123.73, 122.62, 121.88, 121.28, 121.22, 118.29, 112.03, 21.01, 20.68, 20.34, 16.93; FTIR (neat) y 3283, 3013, 1618, 1393, 1301, 1073 cm1; HRMS m/z (EI): calcd. For C22H21N [Mþ] 299.1674, found 299.1674. 4.1.1.10. 7-(2,5-Dimethoxyphenyl)-1,4-dimethoxy-9H-carbazole (3al). Following the general procedure A, 3al was obtained as a White solid (79 mg, 87% yield). Mp 145e147
C; Rf ¼ 0.36 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.38 (s, 1H), 8.24 (d, J ¼ 8.2 Hz, 1H), 7.81e7.67 (m, 1H), 7.35 (dd, J ¼ 8.2, 1.5 Hz, 1H), 7.03 (d, J ¼ 8.9 Hz, 1H), 6.99 (d, J ¼ 3.1 Hz, 1H), 6.92e6.82 (m, 2H), 6.58 (d, J ¼ 8.5 Hz, 1H), 4.02 (s, J ¼ 13.6 Hz, 3H), 3.95 (s, 3H), 3.80 (s, 3H), 3.74 (s, 3H); 13C NMR (75 MHz, Acetone) d 154.86, 151.86, 151.30, 141.34, 140.07, 136.12, 133.50, 132.43, 122.75, 122.53, 121.76, 117.69, 114.24, 114.06, 113.47, 112.64, 107.11, 99.73, 56.64, 56.26, 55.89, 55.85; FTIR (neat) y 3301, 2711, 1278, 1173 cm1; HRMS m/z (EI): calcd. For C22H21NO4 [Mþ] 363.1471, found 363.1472. 4.1.1.11. 9-(Naphthalen-1-yl)-7H-benzo[c]carbazole (3am). Following the general procedure A, 3am was obtained as a White solid (82 mg, 96% yield). Mp 232e234
C; Rf ¼ 0.29 (25% acetone/ hexanes); 1H NMR (300 MHz, CDCl3) d 8.84 (d, J ¼ 8.3 Hz, 1H), 8.65 (d, J ¼ 8.3 Hz, 1H), 8.45 (s, 1H), 8.09e7.99 (m, 2H), 7.98e7.87 (m, 3H), 7.79e7.71 (m, J ¼ 8.3, 6.9, 1.3 Hz, 1H), 7.67e7.63 (m, 2H), 7.59e7.42 (m, 6H); 13C NMR (75 MHz, CDCl3) d 141.79, 139.48, 138.46, 137.96, 134.84, 132.95, 130.85, 130.24, 129.28, 128.49, 128.46, 128.32, 127.93, 127.37, 127.02, 126.79, 126.43, 124.28, 124.09, 124.01, 123.77, 122.53, 116.32, 113.63, 113.52; FTIR (neat) y 3265, 1726, 1317, 1238 cm1; HRMS m/z (EI): calcd. For C26H17N [Mþ] 343.1361, found 343.1360. 4.1.1.12. 5-Methyl-9-(4-methylnaphthalen-1-yl)-7H-benzo[c]carbazole (3an). Following the general procedure A, 3an was obtained as a White solid (87 mg, 94% yield). Mp 240e242
C; Rf ¼ 0.36 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.83 (s, 1H), 8.91 (d, J ¼ 8.2 Hz, 1H), 8.67 (d, J ¼ 8.2 Hz, 1H), 8.19 (d, J ¼ 8.3 Hz, 1H), 8.13 (d, J ¼ 8.4 Hz, 1H), 8.07 (d, J ¼ 8.4 Hz, 1H), 7.77 (dd, J ¼ 7.0, 1.2 Hz, 1H), 7.73 (d, J ¼ 1.0 Hz, 1H), 7.70 (s, 1H), 7.61e7.47 (m, 3H), 7.47e7.42 (m, 3H), 2.84 (s, 3H), 2.76 (s, 3H); 13C NMR (75 MHz, Acetone) d 140.38, 139.93, 139.04, 137.38, 134.30, 134.25, 133.86, 132.96, 131.18, 129.47, 127.73, 127.62, 127.43, 127.10, 126.50, 126.45, 126.20, 125.26, 124.46, 123.84, 123.58, 123.08, 121.88, 114.67, 114.44, 113.63, 20.49, 19.60; FTIR (neat) y 3473, 1724, 1314, 1224 cm1; HRMS m/z (EI): calcd. For C25H21N [Mþ] 371.1674, found 371.1674. 4.1.1.13. 2,3,4-Trimethoxy-7-(2,3,4-trimethoxyphenyl)-9H-carbazole (3ao). Following the general procedure A, 3ao was obtained as a

H.S. Kim et al. / Tetrahedron 73 (2017) 1413e1423

White solid (80 mg, 76% yield). Mp 257e259
C; Rf ¼ 0.32 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.18 (s, 1H), 8.11 (d, J ¼ 8.1 Hz, 1H), 7.56 (d, J ¼ 0.9 Hz, 1H), 7.28 (dd, J ¼ 8.1, 1.5 Hz, 1H), 7.12 (d, J ¼ 8.6 Hz, 1H), 6.88 (t, J ¼ 4.3 Hz, 2H), 4.14 (s, 3H), 3.92 (s, 3H), 3.89 (s, 3H), 3.86 (s, 3H), 3.84 (s, 3H), 3.61 (s, 3H); 13C NMR (75 MHz, Acetone) d 153.88, 153.13, 151.49, 148.41, 142.85, 139.84, 137.43, 135.73, 134.30, 129.44, 124.97, 121.30, 120.83, 120.39, 110.77, 109.41, 107.98, 89.99, 60.55, 60.16, 60.05, 60.03, 55.59, 55.45; FTIR (neat) y 3423, 1684, 1272, 1105 cm1; HRMS m/z (EI): calcd. For C24H25NO6 [Mþ] 423.1682, found 423.1685. 4.1.1.14. 2-Methoxy-7-(4-methoxy-3,5-dimethylphenyl)-1,3dimethyl-9H-carbazole (3ap). Following the general procedure A, 3ap was obtained as a White solid (68 mg, 76% yield). Mp 138e140
C; Rf ¼ 0.44 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.14 (s, 1H), 8.02 (d, J ¼ 8.1 Hz, 1H), 7.75 (s, 1H), 7.68e7.63 (m, 1H), 7.43e7.33 (m, J ¼ 9.0, 2.5 Hz, 3H), 3.78 (s, 3H), 3.74 (s, 3H), 2.49 (s, 3H), 2.42 (s, 3H), 2.34 (s, 6H); 13C NMR (75 MHz, Acetone) d 157.31, 156.32, 142.09, 140.56, 138.58, 138.42, 131.68, 128.38, 123.34, 123.04, 120.67, 119.71, 119.57, 119.03, 113.29, 109.61, 60.55, 59.87, 16.81, 16.38, 10.76; FTIR (neat) y 3261, 1630, 1176, 1024, 978 cm1; HRMS m/z (EI): calcd. For C24H25NO2 [Mþ] 359.1885, found 359.1881. 4.1.1.15. 3-Phenyl-9H-carbazole (3ba). 14a Following the general procedure A, 3ba was obtained as a White solid (48 mg, 79% yield). Mp 204e206
C; Rf ¼ 0.41 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.41 (s, 1H), 8.43 (d, J ¼ 1.7 Hz, 1H), 8.22 (d, J ¼ 7.8 Hz, 1H), 7.77 (t, J ¼ 1.6 Hz, 1H), 7.75 (d, J ¼ 0.9 Hz, 1H), 7.71 (dd, J ¼ 8.5, 1.8 Hz, 1H), 7.62e7.51 (m, 2H), 7.50e7.44 (m, 2H), 7.44e7.37 (m, 1H), 7.35e7.29 (m, 1H), 7.24e7.17 (m, 1H); 1H NMR (300 MHz, Acetone) d 10.43 (s, 1H), 8.50e8.41 (m, 1H), 8.22 (dd, J ¼ 7.8, 0.5 Hz, 1H), 7.83e7.68 (m, 3H), 7.60 (dd, J ¼ 8.4, 0.6 Hz, 1H), 7.56e7.51 (m, 1H), 7.50e7.45 (m, 2H), 7.44e7.38 (m, 1H), 7.36e7.28 (m, 1H), 7.25e7.17 (m, J ¼ 8.1, 7.2, 1.0 Hz, 1H); FTIR (neat) y 3202, 3183, 1406, 1172 cm1; HRMS m/z (EI): calcd. For C18H13N [Mþ] 243.1048, found 243.1044. 4.1.1.16. 2-Methyl-6-(p-tolyl)-9H-carbazole (3bb). Following the general procedure A, 3bb was obtained as a White solid (59 mg, 87% yield). Mp 128e130
C; Rf ¼ 0.35 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.24 (s, 1H), 8.33 (d, J ¼ 1.5 Hz, 1H), 8.06 (d, J ¼ 8.0 Hz, 1H), 7.63 (d, J ¼ 8.2 Hz, 3H), 7.53 (d, J ¼ 8.4 Hz, 1H), 7.32 (s, 1H), 7.29 (s, 1H), 7.26 (s, 1H), 7.03 (d, J ¼ 7.9 Hz, 1H), 2.49 (s, 3H), 2.37 (s, 3H); 13C NMR (75 MHz, Acetone) d 141.98, 140.39, 140.21, 136.51, 132.87, 130.25, 127.62, 125.09, 124.71, 121.93, 121.32, 120.81, 118.64, 111.89, 111.85, 22.08, 21.03; FTIR (neat) y 3163, 3021, 1725, 1674, 1424, 1174 cm1; HRMS m/z (EI): calcd. For C20H17N [Mþ] 271.1361, found 271.1363.

1419

solid (70 mg, 92% yield). Mp 172e174
C; Rf ¼ 0.38 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.34 (s, 1H), 8.42e8.36 (m, 1H), 7.57e7.46 (m, 2H), 7.40 (dd, J ¼ 7.4, 1.8 Hz, 1H), 7.36e7.26 (m, 2H), 7.16e7.02 (m, 3H), 6.72 (d, J ¼ 7.9 Hz, 1H), 4.05 (s, 3H), 3.80 (s, 3H); 13C NMR (75 MHz, Acetone) d 157.71, 157.14, 142.67, 139.23, 132.91, 131.84, 130.57, 128.74, 127.47, 127.35, 124.38, 123.26, 121.59, 113.26, 112.49, 110.33, 104.75, 100.77, 55.89, 55.69; FTIR (neat) y 3315, 3189, 1772, 1539, 1434, 1225, 1062 cm1; HRMS m/z (EI): calcd. For C20H17NO2 [Mþ] 303.1259, found 303.1260. 4.1.1.19. 4-Phenyl-9H-carbazole (3ca). 14a Following the general procedure A, 3ca was obtained as a White solid (13 mg, 21% yield). Mp 163e165
C; Rf ¼ 0.41 (25% acetone/hexanes); 1H NMR (300 MHz, CDCl3) d 8.22 (bs, 1H), 7.67e7.62 (m, 2H), 7.54e7.42 (m, 5H), 7.38e7.33 (m, 3H), 7.17e7.06 (m, 1H), 7.02e6.96 (m, 1H); 13C NMR (75 MHz, CDCl3) d 141.33, 139.93, 139.81, 137.71, 129.26, 128.46, 127.54, 125.65, 125.61, 122.85, 122.42, 121.00, 120.66, 118.94, 110.56, 109.68; FTIR (neat) y 3410, 23600, 2330, 1325 cm1. 4.1.1.20. 3-Methyl-2-phenyl-9H-carbazole (3ga). 14b Following the general procedure A, 3ga was obtained as a White solid (49 mg, 76% yield). Mp 142e144
C; Rf ¼ 0.32 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.28 (s, 1H), 8.13 (d, J ¼ 7.8, 0.5 Hz, 1H), 8.02 (s, 1H), 7.57e7.34 (m, 8H), 7.26e7.13 (m, 1H), 2.40 (s, 3H); 13C NMR (75 MHz, Acetone) d 143.97, 141.61, 141.02, 139.69, 130.27, 129.00, 127.56, 126.53, 126.41, 123.73, 123.44, 122.12, 120.97, 119.68, 112.65, 111.77, 21.07; FTIR (neat) y 3614, 2723, 1528, 1419, 1262 cm1; HRMS m/z (EI): calcd. For C19H15N [Mþ] 257.1204, found 257.1203. 4.1.1.21. 3,7-Dimethyl-2-(p-tolyl)-9H-carbazole (3gb). Following the general procedure A, 3gb was obtained as a White solid (60 mg, 84% yield). Mp 183e185
C; Rf ¼ 0.33 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.12 (s, 1H), 7.96 (d, J ¼ 8.0 Hz, 1H), 7.93 (s, 1H), 7.33e7.23 (m, 6H), 7.00 (d, J ¼ 7.9 Hz, 1H), 2.48 (s, 3H), 2.39 (s, 3H), 2.37 (s, 3H); 13C NMR (75 MHz, Acetone) d 141.99, 141.02, 140.32, 139.64, 136.80, 136.09, 130.08, 129.52, 126.34, 123.32, 121.67, 121.45, 121.09, 120.55, 112.46, 111.73, 22.06, 21.14, 21.01; FTIR (neat) y 3294, 1721, 1459, 1371, 1164 cm1; HRMS m/z (EI): calcd. For C21H19N [Mþ] 285.1517, found 285.1516. 4.1.1.22. 7-Chloro-2-(4-chlorophenyl)-3-methyl-9H-carbazole (3ge). Following the general procedure A, 3ge was obtained as a White solid (45 mg, 55% yield). Mp 164e167
C; Rf ¼ 0.31 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.46 (s, 1H), 8.11 (d, J ¼ 8.3 Hz, 1H), 8.03 (s, 1H), 7.56e7.41 (m, 5H), 7.37 (s, 1H), 7.18 (dd, J ¼ 8.3, 1.8 Hz, 1H), 2.38 (s, 3H); 13C NMR (75 MHz, Acetone) d 142.33, 142.06, 139.92, 139.87, 133.14, 131.84, 131.54, 128.99, 127.05, 122.97, 122.37, 122.24, 122.11, 119.94, 112.74, 111.59, 20.87; FTIR (neat) y 3321, 2841, 1446, 1133, 1012 cm1; HRMS m/z (EI): calcd. For C19H13Cl2N [Mþ] 325.0425, found 325.0422.

4.1.1.17. 2-Chloro-6-(4-chlorophenyl)-9H-carbazole (3be). Following the general procedure A, 3be was obtained as a White solid (53 mg, 68% yield). Mp 157e159
C; Rf ¼ 0.33 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.61 (s, 1H), 8.45 (dd, J ¼ 1.8, 0.6 Hz, 1H), 8.21 (d, J ¼ 8.4 Hz, 1H), 7.80e7.76 (m, 2H), 7.74 (dd, J ¼ 8.5, 1.8 Hz, 1H), 7.62 (dd, J ¼ 8.5, 0.5 Hz, 1H), 7.57 (d, J ¼ 1.8 Hz, 1H), 7.52e7.47 (m, 2H), 7.22 (dd, J ¼ 8.3, 1.9 Hz, 1H); 13C NMR (75 MHz, Acetone) d 142.04, 141.46, 141.00, 132.79, 132.06, 131.81, 129.62, 129.32, 126.01, 124.00, 122.83, 122.38, 120.14, 119.37, 112.43, 111.79; FTIR (neat) y 3193, 2985, 1636, 1290, 1103 cm1; HRMS m/z (EI): calcd. For C18H11Cl2N [Mþ] 311.0269, found 311.0270.

4.1.1.23. 5-Methoxy-2-(2-methoxyphenyl)-3-methyl-9H-carbazole (3gi). Following the general procedure A, 3gi was obtained as a White solid (58 mg, 73% yield). Mp 188e190
C; Rf ¼ 0.34 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 11.10 (s, 1H), 7.98 (s, 1H), 7.42e7.34 (m, 1H), 7.28 (t, J ¼ 8.0 Hz, 1H), 7.20e7.00 (m, 5H), 6.68 (d, J ¼ 7.9 Hz, 1H), 4.02 (s, 3H), 3.70 (s, 3H), 2.16 (s, 3H); 13C NMR (75 MHz, DMSO) d 156.47, 155.66, 141.51, 137.37, 135.49, 131.20, 130.86, 128.64, 126.45, 126.31, 122.48, 121.05, 120.38, 111.55, 111.17, 111.07, 103.99, 99.64, 55.32, 55.19, 19.94; FTIR (neat) y 3445, 3083, 2928, 1602, 1436, 1363 cm1; HRMS m/z (EI): calcd. For C21H19NO2 [Mþ] 317.1416, found 317.1418.

4.1.1.18. 5-Methoxy-3-(2-methoxyphenyl)-9H-carbazole (3bi). Following the general procedure A, 3bi was obtained as a White

4.1.1.24. 7-(2,5-Dimethoxyphenyl)-1,4-dimethoxy-6-methyl-9Hcarbazole (3gl). Following the general procedure A, 3gl was

1420

H.S. Kim et al. / Tetrahedron 73 (2017) 1413e1423

obtained as a White solid (86 mg, 91% yield). Mp 151e153
C; Rf ¼ 0.23 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 11.18 (s, 1H), 7.95 (s, 1H), 7.17 (s, 1H), 7.01 (d, J ¼ 9.0 Hz, 1H), 6.92 (dd, J ¼ 8.9, 3.1 Hz, 1H), 6.85 (d, J ¼ 8.5 Hz, 1H), 6.73 (d, J ¼ 3.0 Hz, 1H), 6.54 (d, J ¼ 8.5 Hz, 1H), 3.96 (s, 3H), 3.92 (s, 3H), 3.73 (s, 3H), 3.62 (s, 3H), 2.17 (s, 3H); 13C NMR (75 MHz, DMSO) d 152.91, 150.57, 149.82, 140.05, 137.31, 135.31, 132.08, 131.00, 126.43, 122.25, 121.28, 116.62, 112.87, 112.38, 112.16, 111.88, 106.18, 98.59, 55.71, 55.48, 55.40, 19.87; FTIR (neat) y 3316, 3204, 1416, 1311 cm1; HRMS m/z (EI): calcd. For C23H23NO4 [Mþ] 377.1627, found 377.1624. 4.1.1.25. 10-Methyl-9-(naphthalen-1-yl)-7H-benzo[c]carbazole (3gm). Following the general procedure A, 3gm was obtained as a White solid (84 mg, 94% yield). Mp 237e239
C; Rf ¼ 0.31 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.84 (s, 1H), 8.92 (t, J ¼ 9.7 Hz, 1H), 8.63 (s, 1H), 8.06 (d, J ¼ 8.1 Hz, 1H), 8.03e7.90 (m, 3H), 7.81 (d, J ¼ 8.8 Hz, 1H), 7.74 (ddd, J ¼ 8.3, 7.0, 1.3 Hz, 1H), 7.62 (dd, J ¼ 8.2, 7.0 Hz, 1H), 7.56e7.38 (m, 6H), 2.24 (s, 3H); 13C NMR (75 MHz, Acetone) d 141.54, 139.12, 138.50, 137.62, 134.59, 133.25, 130.95, 130.08, 130.02, 129.11, 128.76, 128.23, 127.87, 127.71, 127.57, 126.92, 126.90, 126.62, 126.33, 124.37, 124.00, 123.49, 123.24, 115.41, 114.15, 113.64, 20.72; FTIR (neat) y 3152, 2723, 1629, 1424, 1175 cm1; HRMS m/z (EI): calcd. For C27H19N [Mþ] 357.1517, found 357.1513. 4.1.1.26. 3-Methoxy-2-phenyl-9H-carbazole (3ha). Following the general procedure A, 3ha was obtained as a White solid (63 mg, 93% yield). Mp 178e180
C; Rf ¼ 0.29 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.29 (d, J ¼ 48.4 Hz, 1H), 8.14 (d, J ¼ 7.8 Hz, 1H), 7.83 (s, 1H), 7.66e7.56 (m, J ¼ 9.7, 6.0, 3.9 Hz, 2H), 7.51 (dd, J ¼ 8.1, 0.8 Hz, 1H), 7.47e7.39 (m, 3H), 7.38e7.29 (m, 2H), 7.21e7.13 (m, J ¼ 8.0, 7.2, 1.0 Hz, 1H), 3.88 (s, 3H); 13C NMR (75 MHz, Acetone) d 151.78, 141.77, 140.65, 135.79, 130.87, 130.58, 128.64, 127.35, 126.27, 123.95, 123.55, 120.97, 119.31, 113.52, 111.79, 103.36, 56.50; FTIR (neat) y 3252, 2425, 1583, 1463, 1317, 1073 cm1; HRMS m/z (EI): calcd. For C19H15N [Mþ] 273.1154, found 273.1152. 4.1.1.27. 7-(tert-butyl)-2-(4-(tert-butyl)Phenyl)-3-methoxy-9Hcarbazole (3hc). Following the general procedure A, 3hc was obtained as a White solid (63 mg, 65% yield). Mp 226e228
C; Rf ¼ 0.28 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.08 (s, 1H), 8.02 (d, J ¼ 8.3 Hz, 1H), 7.76 (s, 1H), 7.57e7.50 (m, 3H), 7.49e7.40 (m, 3H), 7.27 (dd, J ¼ 8.3, 1.7 Hz, 1H), 3.88 (s, 3H), 1.41 (s, 9H), 1.37 (s, 9H); 13C NMR (75 MHz, Acetone) d 151.82, 149.90, 149.62, 142.10, 137.81, 136.06, 130.26, 130.13, 125.50, 123.39, 121.65, 120.47, 117.42, 113.27, 108.15, 103.11, 56.43, 35.56, 35.00, 32.07, 31.70; FTIR (neat) y 3361, 3072, 1753, 1527, 1273 cm1; HRMS m/z (EI): calcd. For C27H31NO [Mþ] 385.2406, found 385.2403. 4.1.1.28. 7-Fluoro-2-(4-fluorophenyl)-3-methoxy-9H-carbazole (3hf). Following the general procedure A, 3hf was obtained as a White solid (40 mg, 52% yield). Mp 162e164
C; Rf ¼ 0.35 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.32 (s, 1H), 8.11 (dd, J ¼ 8.6, 5.5 Hz, 1H), 7.80 (s, 1H), 7.65e7.57 (m, 2H), 7.43 (d, J ¼ 3.2 Hz, 1H), 7.23 (dd, J ¼ 9.8, 1.9 Hz, 1H), 7.20e7.14 (m, 2H), 6.95 (ddd, J ¼ 9.7, 8.6, 2.3 Hz, 1H), 3.88 (s, 3H); 13C NMR (75 MHz, Acetone) d 164.31, 161.15, 161.07, 152.01, 142.42, 142.26, 136.70, 136.65, 136.22, 136.19, 132.43, 132.33, 129.30, 123.36, 122.27, 122.13, 120.64, 115.48, 115.20, 113.52, 107.50, 107.18, 103.19, 98.34, 97.99, 56.48; FTIR (neat) y 3438, 2714, 1735, 1425, 1273, 1114 cm1; HRMS m/z (EI): calcd. For C19H13F2NO [Mþ] 309.0965, found 309.0963. 4.1.1.29. 3,7-Dimethoxy-2-(4-methoxyphenyl)-9H-carbazole (3hg). Following the general procedure A, 3hg was obtained as a White solid (66 mg, 79% yield). Mp 103e105
C; Rf ¼ 0.27 (25% acetone/

hexanes); 1H NMR (300 MHz, Acetone) d 10.04 (s, 1H), 7.96 (d, J ¼ 8.6 Hz, 1H), 7.69 (s, J ¼ 3.9 Hz, 1H), 7.57e7.48 (m, 2H), 7.35 (s, J ¼ 3.9 Hz, 1H), 7.01 (d, J ¼ 2.2 Hz, 1H), 7.00e6.94 (m, 2H), 6.78 (dd, J ¼ 8.6, 2.3 Hz, 1H), 3.86 (s, 3H), 3.86 (s, 3H), 3.84 (s, 3H); 13C NMR (75 MHz, Acetone) d 159.95, 159.46, 151.95, 143.12, 135.87, 133.02, 131.58, 129.05, 123.53, 121.59, 117.88, 114.07, 112.95, 108.58, 102.92, 95.32, 56.54, 55.67, 55.48; FTIR (neat) y 3311, 2792, 1773, 1427, 1283, 1183 cm1; HRMS m/z (EI): calcd. For C21H19NO3 [Mþ] 333.1365, found 333.1364. 4.1.1.30. 3-Methoxy-5-methyl-2-(o-tolyl)-9H-carbazole (3hh). Following the general procedure A, 3hh was obtained as a White solid (66 mg, 88% yield). Mp 151e153
C; Rf ¼ 0.29 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.23 (s, 1H), 7.79 (s, 1H), 7.35 (d, J ¼ 8.1 Hz, 1H), 7.30e7.19 (m, 6H), 6.95 (d, J ¼ 7.1 Hz, 1H), 3.84 (s, 3H), 2.90 (s, 3H), 2.15 (s, 3H); 13C NMR (75 MHz, Acetone) d 150.90, 140.83, 139.86, 136.77, 134.67, 132.58, 130.09, 129.61, 129.31, 126.93, 125.23, 123.18, 121.67, 119.85, 112.32, 108.54, 104.27, 55.46, 20.00, 19.32; FTIR (neat) y 3341, 3176, 1726, 1697, 1549, 1375, 1220 cm1; HRMS m/z (EI): calcd. For C21H19NO [Mþ] 301.1467, found 301.1465. 4.1.1.31. 10-Methoxy-5-methyl-9-(4-methylnaphthalen-1-yl)-7Hbenzo[c]carbazole (3hn). Following the general procedure A, 3hn was obtained as a White solid (98 mg, 94% yield). Mp 207e210
C; Rf ¼ 0.39 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.66 (s, 1H), 8.92 (d, J ¼ 8.3 Hz, 1H), 8.22 (s, 1H), 8.14 (dd, J ¼ 27.5, 8.4 Hz, 2H), 7.81e7.64 (m, 3H), 7.59e7.49 (m, 3H), 7.47e7.35 (m, 3H), 3.86 (s, 3H), 2.83 (s, J ¼ 5.0 Hz, 3H), 2.76 (s, 3H); 13C NMR (75 MHz, Acetone) d 153.26, 139.26, 137.58, 134.49, 134.21, 133.94, 133.70, 133.47, 131.25, 129.35, 128.27, 128.18, 127.98, 127.32, 126.98, 126.24, 126.13, 126.04, 124.98, 124.57, 124.39, 123.37, 114.98, 114.83, 114.53, 104.11, 100.89, 56.55, 20.50, 19.56; FTIR (neat) y 3404, 2713, 1237, 1173 cm1; HRMS m/z (EI): calcd. For C29H23NO [Mþ] 401.1780, found 401.1778. 4.1.1.32. 3-Fluoro-2-phenyl-9H-carbazole (3ia). Following the general procedure A, 3ia was obtained as a White solid (47 mg, 72% yield). Mp 239e242
C; Rf ¼ 0.31 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.46 (s, 1H), 8.16 (d, J ¼ 7.7 Hz, 1H), 7.97 (d, J ¼ 11.1 Hz, 1H), 7.71e7.34 (m, 8H), 7.26e7.16 (m, 1H); 13C NMR (75 MHz, Acetone) d 156.73, 153.60, 142.33, 137.97, 137.64, 130.13, 130.09, 129.29, 128.25, 127.18, 123.86, 123.73, 123.60, 123.54, 121.42, 119.86, 112.85, 112.80, 112.03, 107.35, 107.01; FTIR (neat) y 3335, 2832, 1583, 1319, 1194 cm1; HRMS m/z (EI): calcd. For C18H12FN [Mþ] 261.0954, found 261.0953. 4.1.1.33. 3-Fluoro-7-methyl-2-(p-tolyl)-9H-carbazole (3ib). Following the general procedure A, 3ib was obtained as a White solid (56 mg, 77% yield). Mp 247e249
C; Rf ¼ 0.34 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.28 (s, 1H), 8.00 (d, J ¼ 8.0 Hz, 1H), 7.88 (d, J ¼ 11.2 Hz, 1H), 7.56e7.48 (m, 3H), 7.34e7.25 (m, 3H), 7.03 (d, J ¼ 8.0 Hz, 1H), 2.49 (s, 3H), 2.40 (d, J ¼ 10.1 Hz, 3H); 13 C NMR (75 MHz, Acetone) d 156.76, 153.65, 142.79, 137.78, 137.67, 137.12, 135.12, 135.11, 129.95, 129.91, 127.50, 127.27, 123.77, 123.64, 121.42, 121.41, 121.35, 121.07, 112.52, 112.47, 111.99, 106.98, 106.63, 22.10, 21.15; FTIR (neat) y 3034, 2713, 1551, 1323, 1217 cm1; HRMS m/z (EI): calcd. For C20H16FN [Mþ] 289.1267, found 289.1265. 4.1.1.34. 3-Fluoro-5-methoxy-2-(2-methoxyphenyl)-9H-carbazole (3ii). Following the general procedure A, 3ii was obtained as a White solid (50 mg, 62% yield). Mp 221e224
C; Rf ¼ 0.35 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 11.30 (s, 1H), 7.83 (d, J ¼ 10.4 Hz, 1H), 7.44e7.29 (m, 4H), 7.17e7.01 (m, 3H), 6.70 (d, J ¼ 8.0 Hz, 1H), 4.03 (s, 3H), 3.74 (s, 3H); 13C NMR (75 MHz, DMSO)

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d 156.76, 155.60, 142.18, 135.19, 131.30, 129.30, 127.20, 125.51, 123.01, 122.75, 121.19, 121.06, 120.37, 112.50, 112.45, 111.39, 111.24, 111.18, 107.36, 107.02, 104.14, 99.66, 55.48, 55.40, 30.69; FTIR (neat) y 3472, 3275, 1474, 1398, 1218 1151 cm1; HRMS m/z (EI): calcd. For C20H16FNO2 [Mþ] 321.1165, found 321.1167. 4.1.1.35. 10-Fluoro-5-methyl-9-(4-methylnaphthalen-1-yl)-7H-benzo [c]carbazole (3in). Following the general procedure A, 3in was obtained as a White solid (84 mg, 86% yield). Mp 219e222
C; Rf ¼ 0.32 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.89 (s, 1H), 8.86 (d, J ¼ 8.2 Hz, 1H), 8.42 (d, J ¼ 11.0 Hz, 1H), 8.19 (d, J ¼ 8.3 Hz, 1H), 8.12 (d, J ¼ 8.4 Hz, 1H), 7.82e7.73 (m, 2H), 7.70e7.63 (m, 2H), 7.61e7.53 (m, 2H), 7.52e7.45 (m, 3H), 2.83 (s, 3H), 2.76 (s, 3H); 13C NMR (75 MHz, Acetone) d 157.62, 155.50, 140.04, 136.22, 135.18, 135.12, 134.47, 133.55, 133.25, 130.97, 129.37, 128.45, 127.68, 127.52, 127.51, 126.99, 126.65, 126.59, 126.22, 125.30, 125.21, 125.02, 124.52, 124.39, 124.23, 123.75, 114.72, 114.67, 114.38, 114.32, 107.79, 107.45, 20.52, 19.59; FTIR (neat) y 3336, 3120, 1636, 1391, 1163, 1021 cm1; HRMS m/z (EI): calcd. For C28H20FN [Mþ] 389.1580, found 389.1581. 4.1.1.36. Methyl 2-phenyl-9H-carbazole-4-carboxylate (3ja). Following the general procedure A, 3ja was obtained as a White solid (39 mg, 52% yield). Mp 126e128
C; Rf ¼ 0.36 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.82 (s, 1H), 8.89 (d, J ¼ 8.0 Hz, 1H), 8.10 (d, J ¼ 26.0 Hz, 2H), 7.78 (d, J ¼ 7.2 Hz, 2H), 7.58 (d, J ¼ 8.0 Hz, 1H), 7.56e7.43 (m, J ¼ 15.8, 7.8 Hz, 3H), 7.44e7.37 (m, 1H), 7.23 (t, J ¼ 7.4 Hz, 1H), 4.21e3.94 (m, 3H); 13C NMR (75 MHz, Acetone) d 168.62, 142.51, 142.30, 141.51, 138.54, 129.86, 128.33, 128.00, 127.51, 126.34, 126.24, 122.28, 122.05, 121.54, 119.94, 114.08, 111.63, 52.45; FTIR (neat) y 3364, 2937, 1472, 1318, 1164 cm1; HRMS m/z (EI): calcd. For C20H15NO2 [Mþ] 301.1103, found 301.1105. 4.1.1.37. Methyl 7-methyl-2-(p-tolyl)-9H-carbazole-4-carboxylate (3jb). Following the general procedure A, 3jb was obtained as a White solid (50 mg, 61% yield). Mp 155e158
C; Rf ¼ 0.27 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.62 (s, 1H), 8.76 (d, J ¼ 8.3 Hz, 1H), 8.10 (d, J ¼ 1.7 Hz, 1H), 7.98 (d, J ¼ 1.7 Hz, 1H), 7.72e7.60 (m, 2H), 7.41e7.28 (m, 3H), 7.05 (dd, J ¼ 8.4, 1.1 Hz, 1H), 4.05 (s, 3H), 2.50 (s, 3H), 2.39 (s, 3H); 13C NMR (75 MHz, Acetone) d 168.68, 142.83, 142.62, 138.75, 138.01, 137.91, 137.56, 130.49, 127.79, 127.78, 126.13, 125.69, 121.78, 121.62, 120.21, 113.71, 111.53, 52.36, 21.98, 21.08; FTIR (neat) y 3326, 3162, 1683, 1427, 1329 cm1; HRMS m/z (EI): calcd. For C22H19NO2 [Mþ] 329.1416, found 329.1417. 4.1.1.38. Methyl 7-fluoro-2-(4-fluorophenyl)-9H-carbazole-4carboxylate (3jf). Following the general procedure A, 3jf was obtained as a White solid (41 mg, 49% yield). Mp 158e160
C; Rf ¼ 0.28(25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.92 (s, 1H), 8.93 (dd, J ¼ 9.0, 5.8 Hz, 1H), 8.13 (d, J ¼ 1.7 Hz, 1H), 8.04 (d, J ¼ 1.7 Hz, 1H), 7.87e7.78 (m, 2H), 7.37e7.22 (m, 3H), 7.07e6.97 (m, 1H), 4.06 (s, 3H); 13C NMR (75 MHz, Acetone) d 168.41, 165.06, 164.75, 161.81, 161.54, 143.26, 143.09, 137.82, 137.78, 137.34, 129.98, 129.87, 128.22, 128.08, 125.80, 122.42, 121.38, 119.05, 116.71, 116.43, 114.16, 108.18, 107.86, 97.94, 97.59, 52.52; FTIR (neat) y 3151, 2849, 1264, 1175 cm1; HRMS m/z (EI): calcd. For C20H13F2NO2 [Mþ] 337.0914, found 337.0912. 4.1.1.39. 2-Methyl-3-phenyl-9H-carbazole (3ka). Following the general procedure A, 3ka was obtained as a White solid (51 mg, 79% yield). Mp 132e134
C; Rf ¼ 0.35 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.27 (s, 1H), 9.63e9.60 (m, 1H), 8.10 (d, J ¼ 7.8 Hz, 1H), 7.93 (s, 1H), 7.54e7.31 (m, 8H), 7.16 (td, J ¼ 7.6, 1.0 Hz, 1H), 2.39 (s, 3H); 13C NMR (75 MHz, Acetone) d 143.88, 141.27, 140.61, 134.46, 133.89, 130.51, 128.85, 127.14, 126.11, 124.08, 122.23,

1421

121.81, 120.75, 119.62, 112.71, 111.65, 21.62; FTIR (neat) y 3263, 3167, 1264, 1167, 932 cm1; HRMS m/z (EI): calcd. For C19H15N [Mþ] 257.1204, found 257.1201. 4.1.1.40. 7-(tert-butyl)-3-(4-(tert-butyl)Phenyl)-2-methyl-9H-carbazole (3kc). Following the general procedure A, 3kc was obtained as a White solid (56 mg, 61% yield). Mp 180e182
C; Rf ¼ 0.32 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.11 (s, 1H), 7.99 (d, J ¼ 8.3 Hz, 1H), 7.85 (s, 1H), 7.53e7.47 (m, 3H), 7.38e7.32 (m, J ¼ 4.2, 2.5 Hz, 3H), 7.26 (dd, J ¼ 8.3, 1.7 Hz, 1H), 2.39 (s, 3H), 1.40 (s, 9H), 1.38 (s, 9H); 13C NMR (75 MHz, Acetone) d 149.70, 149.52, 141.63, 141.08, 140.83, 134.18, 133.36, 130.21, 125.68, 122.30, 121.76, 121.65, 120.27, 117.64, 112.61, 108.11, 35.55, 35.02, 32.11, 31.76, 21.66; FTIR (neat) y 3342, 2914, 1775, 1325, 1224 cm1; HRMS m/z (EI): calcd. For C27H31N [Mþ] 369.2457, found 369.2457. 4.1.1.41. 3-([1,1 0 -Biphenyl]-4-yl)-2-methyl-7-phenyl-9H-carbazole (3kd). Following the general procedure A, 3kd was obtained as a White solid (66 mg, 65% yield). Mp 257e259
C; Rf ¼ 0.38 (25% acetone/hexanes); 1H NMR (300 MHz, DMSO) d 11.28 (s, 1H), 8.17 (d, J ¼ 8.1 Hz, 1H), 8.01 (s, 1H), 7.81e7.68 (m, J ¼ 9.2 Hz, 7H), 7.55e7.34 (m, 10H), 2.44 (s, 3H); 13C NMR (75 MHz, DMSO) d 141.55, 141.26, 140.70, 140.01, 139.95, 138.13, 137.59, 132.85, 132.49, 130.15, 129.00, 128.94, 127.39, 127.03, 126.98, 126.62, 126.39, 121.99, 121.16, 120.61, 120.57, 117.83, 112.06, 108.87, 21.34; FTIR (neat) y 3397, 3264, 1876, 1643, 1275 cm1; HRMS m/z (EI): calcd. For C31H23N [Mþ] 409.1830, found 409.1832. 4.1.1.42. 7-Fluoro-3-(4-fluorophenyl)-2-methyl-9H-carbazole (3kf). Following the general procedure A, 3kf was obtained as a White solid (55 mg, 75% yield). Mp 156e158
C; Rf ¼ 0.31 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.43 (s, 1H), 8.09 (dd, J ¼ 8.6, 5.5 Hz, 1H), 7.90 (s, 1H), 7.48e7.40 (m, 3H), 7.27e7.17 (m, 3H), 6.95 (m, J ¼ 9.8, 8.6, 2.4 Hz, 1H), 2.36 (s, 3H); 13C NMR (75 MHz, Acetone) d 164.20, 161.01, 141.99, 141.82, 141.24, 139.93, 133.81, 133.72, 132.33, 132.22, 122.00, 121.86, 121.69, 120.71, 115.68, 115.40, 112.85, 107.64, 107.32, 98.35, 98.00, 21.48; FTIR (neat) y 3226, 1410, 1232, 1036, 946, 718 cm1; HRMS m/z (EI): calcd. For C19H13F2N [Mþ] 293.1016, found 293.1017. 4.1.1.43. 7-Methoxy-3-(4-methoxyphenyl)-2-methyl-9H-carbazole (3kg). Following the general procedure A, 3kg was obtained as a White solid (63 mg, 79% yield). Mp 164e166
C; Rf ¼ 0.25 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.10 (s, 1H), 7.93 (d, J ¼ 8.5 Hz, 1H), 7.78 (s, 1H), 7.35e7.28 (m, 3H), 7.06e6.97 (m, 3H), 6.78 (dd, J ¼ 8.6, 2.3 Hz, 1H), 3.86 (s, 3H), 3.85 (s, 3H), 2.35 (s, 3H); 13 C NMR (75 MHz, Acetone) d 159.82, 159.28, 142.62, 140.51, 136.24, 134.12, 132.55, 131.47, 122.48, 121.38, 121.05, 117.85, 114.20, 112.42, 108.52, 95.46, 55.67, 55.50, 21.57; FTIR (neat) y 3325, 3064, 1735, 1581, 1264, 1036 cm1; HRMS m/z (EI): calcd. For C21H19NO2 [Mþ] 317.1416, found 317.1415. 4.1.1.44. 7-Fluoro-3-(4-fluoro-2-methylphenyl)-2,5-dimethyl-9Hcarbazole (3kj). Following the general procedure A, 3kj was obtained as a White solid (70 mg, 87% yield). Mp 239e242
C; Rf ¼ 0.37 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.45 (s, 1H), 7.80 (s, 1H), 7.45 (s, J ¼ 11.5 Hz, 1H), 7.19 (dd, J ¼ 8.3, 6.2 Hz, 1H), 7.09 (dd, J ¼ 9.8, 2.2 Hz, 2H), 7.05e6.96 (m, 1H), 6.75 (dd, J ¼ 10.4, 1.3 Hz, 1H), 2.15 (s, 3H), 2.09 (s, J ¼ 1.8 Hz, 3H), 2.08 (s, 3H); 13C NMR (75 MHz, Acetone) d 164.26, 163.81, 161.04, 160.65, 141.83, 141.65, 141.23, 139.91, 139.81, 139.54, 139.50, 135.31, 135.18, 133.59, 133.01, 132.43, 132.33, 123.08, 122.27, 119.08, 116.99, 116.72, 113.03, 112.75, 112.29, 108.90, 108.59, 95.73, 95.38, 20.74, 20.71, 20.27, 20.25; FTIR (neat) y 3471, 2976, 1832, 1527, 1402, 1317, 1162 cm1; HRMS m/z (EI): calcd. For C21H17F2N [Mþ] 321.1329,

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found 321.1328. 4.1.1.45. 2-Methoxy-6-(4-methoxy-3,5-dimethylphenyl)-1,3,7trimethyl-9H-carbazole (3kp). Following the general procedure A, 3kp was obtained as a White solid (86 mg, 92% yield). Mp 155e158
C; Rf ¼ 0.34 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.01 (s, 1H), 7.77 (s, 1H), 7.71 (s, 1H), 7.33 (s, 1H), 7.05 (s, 2H), 3.76 (s, 6H), 2.48 (s, 3H), 2.39 (s, 3H), 2.36 (s, 3H), 2.32 (s, 6H); 13 C NMR (75 MHz, Acetone) d 156.56, 156.05, 141.01, 140.34, 139.43, 134.17, 132.85, 130.93, 130.80, 122.68, 122.55, 121.37, 119.87, 119.56, 113.23, 112.55, 60.52, 59.85, 21.66, 16.80, 16.28, 10.76; FTIR (neat) y 3442, 3184, 1363, 1274, 1165 cm1; HRMS m/z (EI): calcd. For C25H27NO2 [Mþ] 373.2042, found 373.2040. 4.1.1.46. 2-Methoxy-3-phenyl-9H-carbazole (3la). Following the general procedure A, 3la was obtained as a White solid (65 mg, 95% yield). Mp 175e177
C; Rf ¼ 0.33 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.27 (s, 1H), 8.07 (d, J ¼ 7.8 Hz, 1H), 8.01 (s, 1H), 7.64e7.58 (m, J ¼ 5.2, 3.2 Hz, 2H), 7.48 (d, J ¼ 8.1 Hz, 1H), 7.45e7.38 (m, J ¼ 10.2, 4.7 Hz, 2H), 7.35e7.28 (m, J ¼ 8.1, 6.0, 4.2, 2.0 Hz, 2H), 7.21e7.13 (m, 2H), 3.86 (s, 3H); 13C NMR (75 MHz, Acetone) d 157.04, 141.65, 141.02, 140.80, 130.67, 128.58, 126.89, 125.15, 124.39, 124.33, 122.76, 120.17, 119.81, 117.51, 111.48, 94.35, 55.96; FTIR (neat) y 3527, 2372, 1523, 1274, 1137, 821 cm1; HRMS m/z (EI): calcd. For C19H15NO [Mþ] 273.1154, found 273.1152. 4.1.1.47. 2-Methoxy-7-methyl-3-(p-tolyl)-9H-carbazole (3lb). Following the general procedure A, 3lb was obtained as a White solid (59 mg, 78% yield). Mp 186e188
C; Rf ¼ 0.31 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.09 (s, 1H), 7.91 (d, J ¼ 8.2 Hz, 2H), 7.47 (d, J ¼ 8.1 Hz, 2H), 7.30e7.19 (m, 3H), 7.13 (s, 1H), 6.98 (d, J ¼ 7.9 Hz, 1H), 3.84 (s, 3H), 2.46 (s, 3H), 2.37 (s, 3H); 13C NMR (75 MHz, Acetone) d 156.76, 141.54, 141.53, 137.96, 136.18, 134.86, 130.55, 129.24, 124.24, 122.28, 122.13, 121.25, 119.90, 117.68, 111.65, 94.48, 55.98, 21.99, 21.14; FTIR (neat) y 3312, 2791, 1616, 1362, 1184, 1024 cm1; HRMS m/z (EI): calcd. For C21H19NO [Mþ] 301.1467, found 301.1463. 4.1.1.48. 2-Fluoro-3-phenyl-9H-carbazole (3ma). Following the general procedure A, 3ma was obtained as a White solid (43 mg, 66% yield). Mp 242e244
C; Rf ¼ 0.33 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.54 (s, 1H), 8.23 (d, J ¼ 7.8 Hz, 1H), 8.17 (d, J ¼ 7.8 Hz, 1H), 7.70e7.63 (m, 2H), 7.58e7.45 (m, 3H), 7.43e7.32 (m, J ¼ 6.0, 4.9, 1.8 Hz, 3H), 7.27e7.18 (m, 1H); 13C NMR (75 MHz, Acetone) d 161.30, 158.10, 141.76, 141.74, 140.98, 140.81, 138.05, 138.04, 130.10, 130.06, 129.23, 127.74, 126.40, 126.39, 123.76, 123.75, 122.63, 122.56, 121.94, 121.72, 121.03, 121.01, 120.91, 120.90, 120.26, 111.86, 111.85, 98.87, 98.49; FTIR (neat) y 3425, 3167, 2743, 1395, 1172 cm1; HRMS m/z (EI): calcd. For C18H12FN [Mþ] 261.0954, found 261.0951. 4.1.1.49. 2,7-Difluoro-3-(4-fluorophenyl)-9H-carbazole (3mf). Following the general procedure A, 3mf was obtained as a White solid (38 mg, 51% yield). Mp 250e252
C; Rf ¼ 0.37 (25% acetone/ hexanes); 1H NMR (300 MHz, DMSO) d 11.58 (s, 1H), 8.25 (d, J ¼ 7.9 Hz, 1H), 8.16 (dd, J ¼ 8.5, 5.6 Hz, 1H), 7.69e7.60 (m, 2H), 7.39 (d, J ¼ 11.6 Hz, 1H), 7.36e7.27 (m, 3H), 7.07e6.97 (m, 1H); 13C NMR (75 MHz, DMSO) d 163.09, 162.71, 159.86, 159.54, 159.44, 156.24, 141.26, 141.09, 141.07, 140.30, 140.13, 132.86, 132.81, 131.08, 131.04, 130.97, 130.93, 121.67, 121.61, 121.53, 119.53, 119.32, 119.25, 118.99, 115.50, 115.22, 107.23, 106.91, 98.32, 97.95, 97.88, 97.53; FTIR (neat) y 3430, 2391, 1356, 1341, 1387 cm1; HRMS m/z (EI): calcd. For C18H10F3N [Mþ] 297.0765, found 297.0764.

4.1.1.50. 2,7-Difluoro-3-(4-fluoro-2-methylphenyl)-5-methyl-9Hcarbazole (3mj). Following the general procedure A, 3mj was obtained as a White solid (57 mg, 70% yield). Mp 132e134
C; Rf ¼ 0.41 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.70 (s, 1H), 7.95 (d, J ¼ 7.3 Hz, 1H), 7.40e7.32 (m, 2H), 7.17e7.09 (m, 2H), 7.05 (td, J ¼ 8.5, 2.8 Hz, 1H), 6.81 (ddd, J ¼ 10.5, 2.3, 0.8 Hz, 1H), 2.81 (d, J ¼ 7.7 Hz, 3H), 2.23 (s, 3H); 13C NMR (75 MHz, Acetone) d 164.74, 163.93, 161.51, 160.76, 160.47, 157.31, 142.41, 142.38, 142.23, 142.21, 141.80, 141.77, 141.63, 141.61, 140.63, 140.52, 135.54, 135.40, 134.08, 134.04, 133.27, 133.15, 124.83, 124.77, 120.99, 120.84, 120.84, 120.82, 120.81, 120.74, 120.73, 118.70, 117.17, 116.88, 113.24, 112.96, 109.55, 109.23, 98.38, 98.00, 96.07, 95.72, 20.72, 20.70, 20.35, 20.32, 20.31, 20.29; FTIR (neat) y 3325, 1728, 1535, 1240, 1271, 1125 cm1; HRMS m/z (EI): calcd. For C20H14F3N [Mþ] 325.1078, found 325.1075. 4.1.1.51. 7-Fluoro-2-methoxy-6-(4-methoxy-3,5-dimethylphenyl)1,3-dimethyl-9H-carbazole (3mp). Following the general procedure A, 3mp was obtained as a White solid (69 mg, 73% yield). Mp 159e162
C; Rf ¼ 0.41 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.30 (s, 1H), 8.06 (d, J ¼ 7.8 Hz, 1H), 7.78 (s, 1H), 7.29 (d, J ¼ 0.5 Hz, 2H), 7.23 (d, J ¼ 11.6 Hz, 1H), 3.77 (s, 3H), 3.76 (s, 3H), 2.48 (s, 3H), 2.41 (s, 3H), 2.33 (s, 6H); 13C NMR (75 MHz, Acetone) d 160.74, 157.56, 157.07, 156.20, 141.10, 140.93, 140.76, 133.49, 131.26, 130.46, 130.43, 123.39, 121.96, 121.89, 121.55, 121.34, 121.24, 121.21, 119.69, 119.45, 113.49, 98.64, 98.26, 60.54, 59.84, 16.78, 16.31, 10.72; FTIR (neat) y 3127, 2452, 1262, 1153, 1031 cm1; HRMS m/z (EI): calcd. For C24H24FNO2 [Mþ] 377.1791, found 377.1792. 4.1.2. General procedure B for diaryl-substituted carbazole synthesis To a re-sealable pressure tube (13  100 mm) equipped with magnetic stir bar were added o-bromonitrobenzene 1 (0.25 mmol, 100 mol%), aryl boronic acid 2 (0.975 mmol, 390 mol%), Pd(OAc)2 (0.01875 mmol, 7.5 mol%), PPh3 (1.25 mmol, 500 mol %), K2CO3 (1.5 mmol, 600 mol%) and o-DCB (2.5 mL, 0.1 M concentration with respect to o-bromonitrobenzene 1. The mixture was heated at 180
C (oil bath temperature) for 48 h, at which point the reaction mixture was allowed to cool to ambient temperature. The reaction mixture was filtered through a pad of celite and the resulting liquor was concentrated in vacuo and purified by flash column chromatography (SiO2) under the conditions noted to furnish the corresponding product. 4.1.2.1. 2,3-Diphenyl-9H-carbazole (3ea). Following the general procedure B, 3ea was obtained as a White solid (56 mg, 80% yield). Mp 142e144
C; Rf ¼ 0.38 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.47 (s, 1H), 8.23e8.18 (m, 1H), 8.15 (s, 1H), 7.58e7.53 (m, 2H), 7.46e7.39 (m, 1H), 7.26e7.21 (m, 11H); 13C NMR (75 MHz, Acetone) d 143.68, 143.60, 141.77, 140.50, 139.57, 133.12, 131.16, 130.95, 128.63, 128.57, 127.04, 126.71, 126.62, 123.86, 123.50, 122.87, 121.19, 119.94, 113.40, 111.86; FTIR (neat) y 3436, 3371, 2831, 1562, 1256, 1108, 978 cm1; HRMS m/z (EI): calcd. For C24H17N [Mþ] 319.1361, found 319.1361. 4.1.2.2. 7-Methyl-2,3-di-p-tolyl-9H-carbazole (3eb). Following the general procedure B, 3eb was obtained as a White solid (63 mg, 70% yield). Mp 158e160

C; Rf ¼ 0.33 (25% acetone/hexanes); 1H NMR (300 MHz, Acetone) d 10.25 (s, 1H), 8.05e7.99 (m, J ¼ 8.2 Hz, 2H), 7.46 (s, 1H), 7.33 (s, 1H), 7.15e6.95 (m, 10H), 2.49 (s, 3H), 2.28 (s, 6H); 13C NMR (75 MHz, Acetone) d 142.19, 140.95, 140.87, 140.43, 138.94, 136.49, 136.27, 135.80, 132.90, 130.97, 130.79, 129.28, 129.23, 123.44, 122.48, 121.65, 121.42, 120.81, 113.23, 111.87, 22.10, 21.08, 21.07; FTIR (neat) y 3401, 2650, 1367, 1223, 724 cm1; HRMS m/z (EI): calcd. For C27H23N [Mþ] 361.1830, found 361.1829.

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4.1.2.3. 7-Fluoro-2,3-bis(4-fluorophenyl)-9H-carbazole (3ef). Following the general procedure B, 3ef was obtained as a White solid (56 mg, 60% yield). Mp 147e149
C; Rf ¼ 0.31 (25% acetone/ hexanes); 1H NMR (300 MHz, Acetone) d 10.62 (s, 1H), 8.18 (dd, J ¼ 8.6, 5.5 Hz, 1H), 8.11 (s, 1H), 7.53 (s, 1H), 7.29 (dd, J ¼ 10.0, 2.2 Hz, 1H), 7.26e7.18 (m, 5H), 7.05e6.98 (m, 5H); 13C NMR (75 MHz, Acetone) d 171.33, 164.55, 164.12, 163.93, 161.38, 160.88, 160.71, 142.51, 142.34, 141.06, 141.04, 139.62, 139.57, 139.52, 139.48, 138.13, 138.12, 132.90, 132.80, 132.78, 132.67, 132.44, 123.25, 122.61, 122.55, 122.41, 120.42, 115.61, 115.52, 115.32, 115.23, 113.41, 108.11, 107.79, 98.57, 98.22; FTIR (neat) y 3433, 3125, 1773, 1619, 1433 cm1; HRMS m/z (EI): calcd. For C24H14F3N [Mþ] 373.1078, found 373.1080.

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6.

Acknowledgments This work was supported by the 2014 Research Fund of University of Ulsan (2014). Appendix A. Supplementary data

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