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Asymmetric methoxyselenenylation of olefins using an optically active diaryl diselenide derived from d -mannitol
Tetrahedron Letters, Vol. 36, No. 29, pp. 5219-5222. 1995
Pergamon
Elsevier Science Ltd Printed in Great Britain 0040-4039/95 $9,50+0.00
0040-4039(95)00976-0
Asymmetric Methoxyselenenylation of Olefins Using an Optically Active Diaryl Diselenide Derived from D-Mannitol
Ken-ichi Fujita and Kazuhisa Murata National Institute of Materials and Chemical Research, l-l,Higashi, Tsukuba, Ibaraki 305, Japan
Michio lwaoka and Shuji Tomoda* Department of Chemistry, College of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan
Abstract: The diastereomeric excess (d.e.) in asymmetric methoxyselenenylation of trans-~-methylstyrene was significantly enhanced by employing the selenohexafluorophosphate of an optically active diaryl diselenide derived from D-mannitol (97 %d.e.). The procedure was applied to the asymmetric methoxyselenenylation of various olefins.
The addition of electrophilic organoselenium reagents across carbon-carbon double bonds is of extreme importance in selective organic synthesis because it is not only stereospecific in many cases but also applicable to a variety of nucleophiles. ],2 Extension of the reaction to asymmetric methoxyselenenylation has thus far been amply demonstrated by us 3 and others 4,5, but technical problems, such as difficult access to chiral selenium reagents, impractical enantiomeric excess, and limited applicability to various olefins have yet remained unsolved. We have recently reported the asymmetric methoxyselenenylation of chiral selenium reagent 1, which was readily derived from D-mannitol (2), an inexpensive commercially available natural sugar. 6 It was expected that the chirality of the pyrrolidine ring of 1 might be quite effectively transferred to the reaction site through the strong S e " ' N non-bonded interaction between the selenium and the pyrrolidine nitrogen.6,7 Herein we wish to report the versatile usefulness of 1 as a chiral inducer in asymmetric methoxyselenenylation of various olefins. Chiral diaryl diselenide 1 was synthesized according to the method outlined in Scheme 1. Optically active
0.,..~,ph HO HO OH ~OH OH 2
h
H
NaHCO3, KI / DMF, r.t. 1
3 Scheme 1
5219
5220
pyrrolidine with a C2 symmetry 3 was easily obtained by a four-step synthesis from D-mannitol 2 in 55% overall yield. 8 3 was then coupled with di(2-chloromethylphenyl) diselenide 47b according to the improved method9 of our previous synthesis6 to give 1 in enantiomerically pure form in 99% yield. Asymmeaic methoxyselenenylation was carded out as follows (Scheme 2). The procedure employed here was the modified Deziel's synthetic sequence. 4 To a dichloromethane solution10 (2 mi) of 1 (20 rag, 0.020 mmol) a 0. l M tetrachloromethane solution of bromine (0.20 ml) was added dropwise at -78 *C under nitrogen atmosphere. After 20 min stirring, a 0.70 M methanol solution of silver salt (65/~ l, 0.046 mmol) was added. The resulting heterogeneous mixture of selenoester 5 was stirred at -78°C for 20min and then cooled to -100 *C. Then a dichloromethane solution (1 ml) of trans-~-methyistyrene (38 rag, 0.32 mmol) was added at -100 *C. The resulting mixture was stirred for several hours from -100 *C to -40 *C. It was then quenched with aqueous sodium hydrogen carbonate solution and subjected to the usual extractive workup with dichloromethane. The residual oil obtained after evaporation of the solvent was purified by flash column chromatography on silica gel to give the corresponding methoxyselenenylation products ( t a and 6 b) in a decent yield. 11 The d.e.'s of 6 determined by integration of lH NMR absorptions are listed in Table 1. The absolute configuration of the major diastereomer of 6 was determined by the literature method. 3c
1) Br2
Ar*Se-)-= 1
2) AgX / MeOH
u M e OMe '"' ~ , ~ . .
Ph ''~'Me Ar*SeX
additive / CH2CI 2 - 7 8 °C
"
Se/
Me H OMe ~ .
~"'H +
-100 °C --, -40°C Ar*
Ph
./
6a
5
~Ph
Ar*Se
H
6b
Scheme 2 Table. 1 Asymmetric Methoxyselenenylationof trans-B-Methylstyrene Using Various Selenoesters (5)
Yield (%)1)
6a : 6b
Entry
X of 5
Additive
d.e. (%)
12)
Br
none
85
3.2 : 1
52
2
CIO4
none
47
9.0 : 1
80
3
OSO2CF 3
none
68
17 : 1
89
4
BF 4
none
67
18 : 1
90
5
SbF 6
none
64
31 : 1
94
6
PF 6
none
58
37 : 1
95
7
PF6
M.S.4A
75
64 : 1
97
1) Isolatedyield. 2)Reaction carried out by the procedure described in our previous literature.6 The selenoperchlorate (Entry 2) showed significant enhancement in the d.e. of the methoxyselenenylation product 6 (80% d.e.) compared to the corresponding selenenyl bromide (53% d.e.; Entry 1). This suggested that a decrease in the nucleophilicity of the counter anion, i.e. an increase in the electrophilicity of the selenium reagent, may be effective to enhance the d.e. of the reaction. We therefore examined the effect of the
5221
counter anion (Entries 3-6). Among these, the corresponding selenohexafluorophosphate (Entry 6) gave the highest d.e. (95% d.e.). Since these selenoesters were much more reactive than the corresponding selenenyl bromide, the reactions were carried out at lower temperature than that employed for the selenenyl bromide. The high reactivity of the selenoesters should make the transition state of the reaction quite fixed to cause significant enhancement of asymmetric induction. When the reaction of the selenophosphate was performed in the presence of M.S.4A, 6 was obtained in a better chemical and optical yield (75% yield, 97% d.e.; Entry 7). This may be understood by assuming possible activation of methoxyselenenylation by M.S.4A due to its acidic property. The results listed in Table 2 were obtained by employing the method that gave the highest d.e. among the asymmetric methoxyselenenylation reactions described above (Scheme 3).
Ar*Se-)-=
R1
1) Br2 2) AgPFs / MeOH " M.S.4A / CH2CI2 -78 %
R3
_2 Rt OMe Ar*SePF e -100 °C --- --40 °C Ar ::;e R R3 +diastereomer
7a-7h
Scheme 3 Table 2. Asymmetric Methoxyselenenylation of Various Oiefins
Entry
Olefin
1 2
Product Yield of 7 (%)1) d.e. (%)
[~.Me MeO.J~
Me
7a
75
97
7b
74
97
3
[~Me
7c
30
57
4
~
7d
79
42
5
Et ~
7e
87
54
7f
80
52
6
Et
npr . , , , ' ~ , ~ tjPr
7
Et~Et
7g
79
28
8
Q
7h
84
46
1)Isolated yield. It should be noted that various styrene derivatives(Entries 1-4) exclusively gave one regioisomer, ~tmethoxy-13-selenenylation product, under the reaction conditions employed. The trans-disubstituted styrenes(Entries 1 and 2) proceeded with high diastereoselectively (97% d.e. for 7a, 7b). On the other hand, even symmetrical trans-aliphafic olefins(Entries 5 and 6), the facial selectivity of which were considered difficult to control in various asymmetric reactions, 12 gave moderate d.e.'s (54% d.e. for 7e and 52% d.e. for 7f).
5222
Furthermore symmetrical cis-aliphatic olefins(Entries 7 and 8) gave only slightly less d.e.'s (28% d.e. for 7 g, 46% d.e. for 7 h) than those for 7 e and 7f despite that the d.e.-determining step for cis-olefin is not the facial stereoselection step of optically modified selenenyl cation but the one involving capture of the nucleophile as previously described.:~1 We are currently trying to apply this method to the intramolecular asymmetric oxyselenenylation and to the synthesis of natural products. The results will be reported in due course. REFERENCES AND NOTES 1.
a) Organoselenium Chemistry; Liotta, D. Ed.; Wiley: London, 1987. b) Selenium Reagents and
Intermediates in Organic Synthesis; Paulmier, C. Ed.; Pergamon Press: Oxford, 1986. 2.
a) Schmid, G. H.; Garratt, D. G. In The Chemistry of Double-Bonded Functional Groups; Patai, S. Ed., Wiley: London, 1977; Supp. A, Part 2 b) Garratt, D. G.; Kabo, A. Can. J. Chem. 19811, 58, 10301041.
3.
4. 5. 6. 7. 8. 9.
10.
a) Tomoda, S.; Iwaoka, M.; Chem. Lett., 1988, 1895-1898; b) Tomoda, S.; Fujita, K.; Iwaoka, M. J.
Chem.Soc., Chem. Commun., 1990, 129-131. c) Tomoda, S.; Fujita, K.; lwaoka, M. Phosphorus, Sulfur, and Silicon, andthe Related Elements, 1992, 67, 125-130. d) Fujita, K.; Murata, K.; Iwaoka, M.; Tomoda, S. Heteroatom Chem., 19 95, in press. Deziel, R.; Goulet, S.; Grenier, L.; Bordeleau, J.; Bernier, J. J. Org. Chem., 1993, 58, 3619-3621. Fukuzawa, S.; Kasugahara, Y.; Uemura, S. TetrahedronLett., 1994, 35, 9403-9406. Fujita, K.; Iwaoka, M.; Tomoda, S. Chem. Lett., 1994, 923-926. a) lwaoka, M.; Tomoda, S. J. Am. Chem. Soc., 1994, 116, 2557-2561. b) Iwaoka, M.; Tomoda, S. Phosphorus, Sulfur, and Silicon, and the Related Elements, 19 92, 67, 125-128. a) Shing, Tony K. M. Tetrahedron, 1988, 44, 7261-7264. b) Masaki, Y.; Oda, H.; Kazuta, K.; Usui, A.; ltoh, A.; Xu, F. TetrahedronLett., 1992, 33, 5089-5092. 3 and 4 were dissolved in N, N-dimethylformamide (DMF) and the solution was stirred at room temperature in the presence of slightly excess amount of sodium hydrogen carbonate and excess amount of (3 eq) potassium iodide. The spectral data of 1 was reported previously.6 The effect of solvent on the magnitude of d.e. was examined by preparing 5 (X=OSO2CF3); diethyl ether: 83% d.e., tetrahydrofuran: 65% d.e., 1,2-dimethoxyethane: 27% d.e.
11.
spectral dataof6 IR (neat) 2900, 2840, 1448, 1385, 1120, 1080, 1018, 750 can-l; 1H NMR (CDCI3) (ppm) 7.72 -7.12 (m, 19H, ArH), 5.51 (s, 0.015×2H, CHPh), 5.50 (s, 0.985 ×2H, CHPh), 4.80 (d, J = 16 Hz, 0.0153< 1H, CH2N), 4.75 (d, J = 16 Hz, 0.985>( IH, CH2N), 4.46 (d, J =4.4 Hz, 0.015× 1H, MeOCH), 4.41 (d, J =2.3 Hz, 2H, OCHCHO), 4.36 (d, J = 4.4 Hz, 0.985× IH, MeOCH), 4.13 (d, J = 13 Hz, 2H, OCH2), 3.99 (d, J = 16 Hz, 0.015>(1H, CH2N), 3.94 (dd, J = 13, 2.3 Hz, 2H, OCH2), 3.91 (d, J = 16 Hz, 0.985)< 1H, CH2N), 3.52 (s, 2H, NCH), 3.52-3.48 (m, 1H, SeCH), 3.28 (s, 0.015>(3H, OCH3), 3.26 (s, 0.985>(3H, OCH3), 1.37 (d, J = 7.1 Hz, 0.985X3H, CH3), 1.33 (d,
12.
J = 7.1 Hz, 0.015 × 3H, CH3); HRMS Found: m/z 657.1853. Calcd for C 37H39NO5Se: M, 657.1991. a) Jacobsen, E. N.; Marko, I.; Mungall, W. S.; Schroder, G.; Sharpless, K. B. J. Am. Chem. Soc., 1988,
110, 1968-1970. b) Groves, J. T.; Viski, P. J. Org. Chem., 1990, 55, 3628-3634.
(Received in Japan 11 March 1995; revised 18 May 1995; accepted 23 May 1995)
Pergamon
Elsevier Science Ltd Printed in Great Britain 0040-4039/95 $9,50+0.00
0040-4039(95)00976-0
Asymmetric Methoxyselenenylation of Olefins Using an Optically Active Diaryl Diselenide Derived from D-Mannitol
Ken-ichi Fujita and Kazuhisa Murata National Institute of Materials and Chemical Research, l-l,Higashi, Tsukuba, Ibaraki 305, Japan
Michio lwaoka and Shuji Tomoda* Department of Chemistry, College of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan
Abstract: The diastereomeric excess (d.e.) in asymmetric methoxyselenenylation of trans-~-methylstyrene was significantly enhanced by employing the selenohexafluorophosphate of an optically active diaryl diselenide derived from D-mannitol (97 %d.e.). The procedure was applied to the asymmetric methoxyselenenylation of various olefins.
The addition of electrophilic organoselenium reagents across carbon-carbon double bonds is of extreme importance in selective organic synthesis because it is not only stereospecific in many cases but also applicable to a variety of nucleophiles. ],2 Extension of the reaction to asymmetric methoxyselenenylation has thus far been amply demonstrated by us 3 and others 4,5, but technical problems, such as difficult access to chiral selenium reagents, impractical enantiomeric excess, and limited applicability to various olefins have yet remained unsolved. We have recently reported the asymmetric methoxyselenenylation of chiral selenium reagent 1, which was readily derived from D-mannitol (2), an inexpensive commercially available natural sugar. 6 It was expected that the chirality of the pyrrolidine ring of 1 might be quite effectively transferred to the reaction site through the strong S e " ' N non-bonded interaction between the selenium and the pyrrolidine nitrogen.6,7 Herein we wish to report the versatile usefulness of 1 as a chiral inducer in asymmetric methoxyselenenylation of various olefins. Chiral diaryl diselenide 1 was synthesized according to the method outlined in Scheme 1. Optically active
0.,..~,ph HO HO OH ~OH OH 2
h
H
NaHCO3, KI / DMF, r.t. 1
3 Scheme 1
5219
5220
pyrrolidine with a C2 symmetry 3 was easily obtained by a four-step synthesis from D-mannitol 2 in 55% overall yield. 8 3 was then coupled with di(2-chloromethylphenyl) diselenide 47b according to the improved method9 of our previous synthesis6 to give 1 in enantiomerically pure form in 99% yield. Asymmeaic methoxyselenenylation was carded out as follows (Scheme 2). The procedure employed here was the modified Deziel's synthetic sequence. 4 To a dichloromethane solution10 (2 mi) of 1 (20 rag, 0.020 mmol) a 0. l M tetrachloromethane solution of bromine (0.20 ml) was added dropwise at -78 *C under nitrogen atmosphere. After 20 min stirring, a 0.70 M methanol solution of silver salt (65/~ l, 0.046 mmol) was added. The resulting heterogeneous mixture of selenoester 5 was stirred at -78°C for 20min and then cooled to -100 *C. Then a dichloromethane solution (1 ml) of trans-~-methyistyrene (38 rag, 0.32 mmol) was added at -100 *C. The resulting mixture was stirred for several hours from -100 *C to -40 *C. It was then quenched with aqueous sodium hydrogen carbonate solution and subjected to the usual extractive workup with dichloromethane. The residual oil obtained after evaporation of the solvent was purified by flash column chromatography on silica gel to give the corresponding methoxyselenenylation products ( t a and 6 b) in a decent yield. 11 The d.e.'s of 6 determined by integration of lH NMR absorptions are listed in Table 1. The absolute configuration of the major diastereomer of 6 was determined by the literature method. 3c
1) Br2
Ar*Se-)-= 1
2) AgX / MeOH
u M e OMe '"' ~ , ~ . .
Ph ''~'Me Ar*SeX
additive / CH2CI 2 - 7 8 °C
"
Se/
Me H OMe ~ .
~"'H +
-100 °C --, -40°C Ar*
Ph
./
6a
5
~Ph
Ar*Se
H
6b
Scheme 2 Table. 1 Asymmetric Methoxyselenenylationof trans-B-Methylstyrene Using Various Selenoesters (5)
Yield (%)1)
6a : 6b
Entry
X of 5
Additive
d.e. (%)
12)
Br
none
85
3.2 : 1
52
2
CIO4
none
47
9.0 : 1
80
3
OSO2CF 3
none
68
17 : 1
89
4
BF 4
none
67
18 : 1
90
5
SbF 6
none
64
31 : 1
94
6
PF 6
none
58
37 : 1
95
7
PF6
M.S.4A
75
64 : 1
97
1) Isolatedyield. 2)Reaction carried out by the procedure described in our previous literature.6 The selenoperchlorate (Entry 2) showed significant enhancement in the d.e. of the methoxyselenenylation product 6 (80% d.e.) compared to the corresponding selenenyl bromide (53% d.e.; Entry 1). This suggested that a decrease in the nucleophilicity of the counter anion, i.e. an increase in the electrophilicity of the selenium reagent, may be effective to enhance the d.e. of the reaction. We therefore examined the effect of the
5221
counter anion (Entries 3-6). Among these, the corresponding selenohexafluorophosphate (Entry 6) gave the highest d.e. (95% d.e.). Since these selenoesters were much more reactive than the corresponding selenenyl bromide, the reactions were carried out at lower temperature than that employed for the selenenyl bromide. The high reactivity of the selenoesters should make the transition state of the reaction quite fixed to cause significant enhancement of asymmetric induction. When the reaction of the selenophosphate was performed in the presence of M.S.4A, 6 was obtained in a better chemical and optical yield (75% yield, 97% d.e.; Entry 7). This may be understood by assuming possible activation of methoxyselenenylation by M.S.4A due to its acidic property. The results listed in Table 2 were obtained by employing the method that gave the highest d.e. among the asymmetric methoxyselenenylation reactions described above (Scheme 3).
Ar*Se-)-=
R1
1) Br2 2) AgPFs / MeOH " M.S.4A / CH2CI2 -78 %
R3
_2 Rt OMe Ar*SePF e -100 °C --- --40 °C Ar ::;e R R3 +diastereomer
7a-7h
Scheme 3 Table 2. Asymmetric Methoxyselenenylation of Various Oiefins
Entry
Olefin
1 2
Product Yield of 7 (%)1) d.e. (%)
[~.Me MeO.J~
Me
7a
75
97
7b
74
97
3
[~Me
7c
30
57
4
~
7d
79
42
5
Et ~
7e
87
54
7f
80
52
6
Et
npr . , , , ' ~ , ~ tjPr
7
Et~Et
7g
79
28
8
Q
7h
84
46
1)Isolated yield. It should be noted that various styrene derivatives(Entries 1-4) exclusively gave one regioisomer, ~tmethoxy-13-selenenylation product, under the reaction conditions employed. The trans-disubstituted styrenes(Entries 1 and 2) proceeded with high diastereoselectively (97% d.e. for 7a, 7b). On the other hand, even symmetrical trans-aliphafic olefins(Entries 5 and 6), the facial selectivity of which were considered difficult to control in various asymmetric reactions, 12 gave moderate d.e.'s (54% d.e. for 7e and 52% d.e. for 7f).
5222
Furthermore symmetrical cis-aliphatic olefins(Entries 7 and 8) gave only slightly less d.e.'s (28% d.e. for 7 g, 46% d.e. for 7 h) than those for 7 e and 7f despite that the d.e.-determining step for cis-olefin is not the facial stereoselection step of optically modified selenenyl cation but the one involving capture of the nucleophile as previously described.:~1 We are currently trying to apply this method to the intramolecular asymmetric oxyselenenylation and to the synthesis of natural products. The results will be reported in due course. REFERENCES AND NOTES 1.
a) Organoselenium Chemistry; Liotta, D. Ed.; Wiley: London, 1987. b) Selenium Reagents and
Intermediates in Organic Synthesis; Paulmier, C. Ed.; Pergamon Press: Oxford, 1986. 2.
a) Schmid, G. H.; Garratt, D. G. In The Chemistry of Double-Bonded Functional Groups; Patai, S. Ed., Wiley: London, 1977; Supp. A, Part 2 b) Garratt, D. G.; Kabo, A. Can. J. Chem. 19811, 58, 10301041.
3.
4. 5. 6. 7. 8. 9.
10.
a) Tomoda, S.; Iwaoka, M.; Chem. Lett., 1988, 1895-1898; b) Tomoda, S.; Fujita, K.; Iwaoka, M. J.
Chem.Soc., Chem. Commun., 1990, 129-131. c) Tomoda, S.; Fujita, K.; lwaoka, M. Phosphorus, Sulfur, and Silicon, andthe Related Elements, 1992, 67, 125-130. d) Fujita, K.; Murata, K.; Iwaoka, M.; Tomoda, S. Heteroatom Chem., 19 95, in press. Deziel, R.; Goulet, S.; Grenier, L.; Bordeleau, J.; Bernier, J. J. Org. Chem., 1993, 58, 3619-3621. Fukuzawa, S.; Kasugahara, Y.; Uemura, S. TetrahedronLett., 1994, 35, 9403-9406. Fujita, K.; Iwaoka, M.; Tomoda, S. Chem. Lett., 1994, 923-926. a) lwaoka, M.; Tomoda, S. J. Am. Chem. Soc., 1994, 116, 2557-2561. b) Iwaoka, M.; Tomoda, S. Phosphorus, Sulfur, and Silicon, and the Related Elements, 19 92, 67, 125-128. a) Shing, Tony K. M. Tetrahedron, 1988, 44, 7261-7264. b) Masaki, Y.; Oda, H.; Kazuta, K.; Usui, A.; ltoh, A.; Xu, F. TetrahedronLett., 1992, 33, 5089-5092. 3 and 4 were dissolved in N, N-dimethylformamide (DMF) and the solution was stirred at room temperature in the presence of slightly excess amount of sodium hydrogen carbonate and excess amount of (3 eq) potassium iodide. The spectral data of 1 was reported previously.6 The effect of solvent on the magnitude of d.e. was examined by preparing 5 (X=OSO2CF3); diethyl ether: 83% d.e., tetrahydrofuran: 65% d.e., 1,2-dimethoxyethane: 27% d.e.
11.
spectral dataof6 IR (neat) 2900, 2840, 1448, 1385, 1120, 1080, 1018, 750 can-l; 1H NMR (CDCI3) (ppm) 7.72 -7.12 (m, 19H, ArH), 5.51 (s, 0.015×2H, CHPh), 5.50 (s, 0.985 ×2H, CHPh), 4.80 (d, J = 16 Hz, 0.0153< 1H, CH2N), 4.75 (d, J = 16 Hz, 0.985>( IH, CH2N), 4.46 (d, J =4.4 Hz, 0.015× 1H, MeOCH), 4.41 (d, J =2.3 Hz, 2H, OCHCHO), 4.36 (d, J = 4.4 Hz, 0.985× IH, MeOCH), 4.13 (d, J = 13 Hz, 2H, OCH2), 3.99 (d, J = 16 Hz, 0.015>(1H, CH2N), 3.94 (dd, J = 13, 2.3 Hz, 2H, OCH2), 3.91 (d, J = 16 Hz, 0.985)< 1H, CH2N), 3.52 (s, 2H, NCH), 3.52-3.48 (m, 1H, SeCH), 3.28 (s, 0.015>(3H, OCH3), 3.26 (s, 0.985>(3H, OCH3), 1.37 (d, J = 7.1 Hz, 0.985X3H, CH3), 1.33 (d,
12.
J = 7.1 Hz, 0.015 × 3H, CH3); HRMS Found: m/z 657.1853. Calcd for C 37H39NO5Se: M, 657.1991. a) Jacobsen, E. N.; Marko, I.; Mungall, W. S.; Schroder, G.; Sharpless, K. B. J. Am. Chem. Soc., 1988,
110, 1968-1970. b) Groves, J. T.; Viski, P. J. Org. Chem., 1990, 55, 3628-3634.
(Received in Japan 11 March 1995; revised 18 May 1995; accepted 23 May 1995)