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Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols
Accepted Manuscript Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols Pratip Kumar Dutta, Arpi Majumder, Sanjay Dutta, Basab Bijayi Dhar, Parthapratim Munshi, Subhabrata Sen PII: DOI: Reference:
S0040-4039(16)31730-0 http://dx.doi.org/10.1016/j.tetlet.2016.12.074 TETL 48486
To appear in:
Tetrahedron Letters
Received Date: Revised Date: Accepted Date:
27 November 2016 21 December 2016 23 December 2016
Please cite this article as: Kumar Dutta, P., Majumder, A., Dutta, S., Bijayi Dhar, B., Munshi, P., Sen, S., Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols, Tetrahedron Letters (2016), doi: http://dx.doi.org/10.1016/j.tetlet.2016.12.074
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Graphical Abstract
Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols
Leave this area blank for abstract info.
Pratip Kumar Dutta,1, § Arpi Majumder,2, § Sanjay Dutta,1 Basab Bijayi Dhar,1 Parthapratim Munshi1 and Subhabrata Sen*, 1
1
Tetrahedron Letters
Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols Pratip Kumar Dutta,1, § Arpi Majumder,2, § Sanjay Dutta,1 Basab Bijayi Dhar,1 Parthapratim Munshi1 and Subhabrata Sen*, 1 a
Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Dadri, Chithera, Gautam Budh Nagar, Uttar Pradesh 201314, India LNM Institute of Information Technology, Jaipur - 302 031, India § Equal contributors b
A RT I C L E I N F O
A BS T RA C T
Article history: Received Received in revised form Accepted Available online
An efficient solvent free Pd(PCH2S)2dba catalyzed green-chemical strategy for the synthesis of diaryl disulfides from aryl thiols in moderate to excellent yield is reported. Variety of diaryl disulfides were synthesized. The catalyst is recyclable up to four cycles. 2009 Elsevier Ltd. All rights reserved .
Keywords: Diaryl disulphides Aryl thiol Pd(PCH2S)2dba Green Chemistry DFT calculations
1. Introduction Diaryl disulfide moieties are extremely important as they have multifaceted applications in pharmaceutical industry as well as in the field of material science.1 They are used as novel stabilizer for the tumor suppressor Pdcd4, they are applied to solve sulfur deposition problems in sour gas fields, facilitate a gamut of addition and exchange reactions and by virtue of the reversibility of S-S bond formation, play an integral role in the synthesis of bioactive compounds.2-5 Interestingly polysulfide compounds are frequently used as polymers in rubber industry. In addition compounds with disulfide linkages are used to design lithium ion batteries.6 Due to all these special characteristics and applications, diaryl disulfides are extremely coveted targets for synthesis. Among the strategies used for the synthesis of diaryl disulfides, base mediated oxidation of thiols in presence of a variety of metal oxidants is most commonly harnessed.7 However, effectiveness of this strategy is lessened due to the usage of expensive and toxic reagents and long reaction times. Very recently Carril et al. reported a base mediated metal free aqueous synthesis of diaryl disulfides.8 Stoichiometric triphenyl phosphines are also used to couple arylsulphonates to generate diaryl disulfides at ambient temperature.9 Firouzabadi et al. have also reported a one-pot synthesis of diaryl disulfides with carbon disulfide (CS2) as a sulfur surrogate, with diethylamine and catalytic copper iodide (CuI) in PEG200.10 Keeping in mind the industrial utility of diaryl disulfides and their applications as diverse building blocks, generating a green
chemical strategy for the synthesis of these compounds is an attractive proposition. In this regard, a metal catalyzed, solvent free protocol for the synthesis of these compounds is highly desirable. Here in we report a Pd(PCH2S)2dba catalyzed, solvent free synthesis of diaryl disulfides from the corresponding aryl thiols in moderate to good yields. 2. Results and discussions The catalyst Pd(PCH2S)2dba was discovered by Aizawa et al. It has demonstrated remarkable efficiency in cesium carbonate mediated C-N and C-O bond forming reactions.11-12 To further investigate the utility of this catalyst in the coupling of arylthiols optimization study involving reaction of 1 with 5 mol% of the catalyst in variety of solvents and bases (Table S1, supplementary information) resulted in providing compound 2a under a solvent free reaction condition as depicted in Scheme 1 below.
Scheme 1. Optimization reaction of 2a
2
Tetrahedron
Next we investigated the robustness of this protocol by reacting variety of aryl thiophenols under the optimized condition. From various diaryl disulfides 2a-k, synthesized we could observe that aryl thiols with electron donating substituents are more amenable towards the optimized condition, as they were synthesized in higher yields compared to the electron withdrawing analogs. The position of the functionalities at ortho, meta or para on aryl thiol impart some influence in the reaction as observed in the formation of bromo analogs 2b and 2g (Scheme 2). Interestingly the yield of o, m and p-methoxy
derivatives 2f, i and j was not influenced with the orientation of the methoxy funcationalty (Scheme 2). There was no reaction for the aliphatic thiols and the only heteroaromatic thiol 2k was synthesized in poor yields (25%) (Scheme 2). The compounds were characterized by 1H/ 13C-NMR and high resolution mass spectroscopy. The structure of the final products was confirmed by the representative single crystal X-ray crystallography of compound 2a and was corroborated with the latest reported structure in the chemical crystallographic database (CCDC# 722274).13
Scheme 2. Variety of analogs of diaryl dithiols via the optimized procedure The tentative mechanism of dimerization of aryl thiols is depicted in Scheme 3. We envision consecutive oxidative addition of aryl thiols onto Pd(PCH2S)2dba that may lead to the formation of intermediate B which then undergoes reductive elimination through intermediate C to generate the desired diaryl disulfides 2a-k along with the catalyst (Scheme 1). We assume that higher Pd-S bond energy (~91 kcal mol-1) over Pd-alkene bond energy (~19 kcal mol-1) thermodynamically initiates the catalytic process.14-15 Two Pd-S bonds are formed consecutively that led to the formation of a three membered transition state. To support the proposed catalytic cycle, no product formation was observed with pyridine 2-thiol (a chelating ligand). This may be because the chelating nature of pyridine 2-thiol, prevents simultaneous attack of two thiol moieties on the Pd center to form three membered transition state. Interestingly for pyridine 3-thiol, the desired product 2k was obtained in ~25% yield. This is because the chelation may be less favorable due to longer distance between pyridinic-nitrogen and the thiol moiety.
Scheme 3. Outline of the proposed catalytic cycle for dimerization reaction. To support our putative mechanism, we wanted to investigate the stability of the proposed transition state C (Scheme 1).
3 Accordingly, we performed DFT calculation using Gaussian09 and optimized the structure using B3LYP functional and DZP basis set.16-18 To our utmost gratification, the structure of C was found to be stable as shown in Figure 1. Further, to assess the stability of C, the structure was optimized by performing TDDFT calculation using the same level of theory (C˝). Although the excited state structures C´ and C˝ (Figure 1) underwent some conformational changes but the coordination of Pd-atom with the four S-atoms and the other bond connectivity remained unchanged. The corresponding energy of the excited state of the structure was estimated to be -8681.972 Hartree.
3. Conclusions To summarize we have reported a “green” synthesis of diaryl disulfides from aryl thiols in moderate to good yield. A solvent free protocol with relatively inexpensive thiols as substrates and Pd(PCH2S)2dba as catalyst provides a highly feasible methodology. The products are purified by column chromatography. The catalyst is recyclable to nearly four cycles. The proposed mechanism with DFT calculation tried to provide an insight into the catalyst mediated dimerization of the thiophenols. Efforts are in progress to simplify the purification process through extraction and precipitation so that it will have an overall appeal in the industry. 4. Acknowledgments This research was supported by Shiv Nadar University and Department of Science and Technology. AM is thankful to Department of Science and Technology (DST), Govt. of India for awarding WOS-A fellowship (SR/WOS-A/CS-29/2010). AM expresses her heartiest gratitude to Prof. S. Aizawa, Graduate School of Science and Engineering, University of Toyama, Japan for his guidance in the preparation of the catalysts during her post-doc tenure in his lab. She is also grateful to Dr. Ragini Gupta, Department of Chemistry, Malaviya National Institute of Technology, JLN Marg, Jaipur 302 017, India for being the mentor in the Department of Science and Technology project.
Figure 1. Optimized structure of C using DFT (C´) and TDDFT (C˝) In order to assess the economic viability of the catalyst, we aimed at reusability of Pd(PCH2S)2dba catalyst for dimerization reaction. As shown in Fig. 2, catalyst was recycled for the dimerization of thiophenyl in acetonitrile. The %ge yield depicted in the figure is the isolated yield of the product after each cycle. The catalyst exhibited very good activity for the first two consecutive recycles and modest decrease in conversion was observed during third and fourth cycle. In the fifth cycle however the catalyst activity was nearly half of the first cycle. The decrease in yield since third cycle may be because of loss of catalyst due to handling. The leaching of palladium in solution was checked by ICP-AES analysis of the reaction mixture that indicated palladium content below detectable level (0.01 ppm), which revealed no significant leaching of palladium catalyst.
References and notes 1.
2.
3. 4. 5. 6. 7.
8.
9. 10. 11. 12.
Figure 2. Recyclability study of Pd(PCH2S)2dba catalyst in aqueous medium.
13. 14.
(a) Arisawa, M.; Fujimoto, K.; Morinaka, S.; Yamaguchi, M.; J. Am. Chem. Soc. 2005, 127, 12226; (b) Nishiyama, Y.; Kawamatsu, H; Sonoda, N.; J. Org. Chem. 2005, 70, 2551. (c) Ferris, K. F.; Franz, J. A.; J. Org. Chem. 1992, 57, 777; (d) Antebi, S.; Alper, H.; Tetrahedron Lett. 1985, 26, 2609; (e) Ogawa, A.; Nishiyama, Y.; Kambe, N.; Murai, S.; Sonoda, N.; Tetrahedron Lett. 1987, 28, 3271; (f) W.; Zaharevitz, D.; Summers, M. F.; Wallqvist, A.; Covell, D. G.; J. Med. Chem. 1996, 39, 3606; (g) Dougherty, G.; Haas, O. J. Am. Chem. Soc. 1937, 59, 2469. Schmid, T.; Blees, J. S.; Bajer, M. M.; Wild, J.; Pescatori, L.; Crucitti, G. C.; Scipione, L.; Costi, R.; Henrich, C. J.; Brüne, B.; Colburn, N. H.; Di Santo, R.; PLoS One 2016, 11, e0151643. Voorhees, R. J.; Thomas, E. R.; Kennelley, K. J.; Oil and Gas Journal 1991, 89, 85. Tanaka, K.; Ajiki, K. A.; Tetrahedron Lett. 2004, 45, 5677. (a) Kondo, T.; Mitsudo, T. –A.; Chem. Rev., 2000, 100, 3205; (b) Kumar, S.; Engman, L.; J. Org. Chem., 2006, 71, 5400. Maddanimath, T.; Khollam, Y. B.; Aslam, M.; Mulla, I. S.; Vijayamohanan, K.; J. Power Sources, 2003, 124, 133. (a) Karami, B.; Montazerozohori, M.; Habibi, M. H.; Molecules, 2005, 10, 1358; (b) Iranpoor, N.; Zeynizadeh, B.; Synthesis, 1999, 49; (c) Chauhan, S. M. S.; Kumar, A.; Srinivas, K. A.; Chem. Commun., 2003, 2348; (d) Patel, S.; Mishra, B. K.; Tetrahedron Lett., 2004, 45, 1371; (e) Arisawa, M.; Sugata, C.; Yamaguchi, M.; Tetrahedron Lett., 2005, 46, 6097; (f) Cochran, J. C.; Friedman, S. R.; Frazier, J. P.; J. Org. Chem. 1996, 61, 1533. (a) Carril, M.; SanMartin, R.; Domínguez, E.; Tellitu, I.; Green Chemistry, 2007, 9, 315; (b) Nӧel, T.; Talla, A.; Driessen, B.; Straathof, N. J. W.; Milroy, L. Brunsveld, L.; Hessel, V.; Advance synthesis and Catalysis,2015, 135, 2180. Kabalka, G. W.; Reddy, M. S.; Yao, M. –L.; Tetrahedron Lett. 2009, 50, 7340. Firouzabadi, H.; Iranpoor, N.; Samadi, A.; Tetrahedron Lett. 2014, 55, 1212. Aizawa, S.-H.; Mazumder, A.; Yokohama, Y.; Tamai, M.; Maeda. D.; Kitamura, A.; Organometallics, 2009, 28, 6067. Mazumder, A.; Gupta, R.; Mandal, M.; Babu, M.; Chakraborty, D.; Journal of Organometallic Chemistry, 2015, 781, 23. Mijoviloch, A.; Pettersson, L. G.; de Groot. F. M.; Weckhuysen, B. M.; J. Phys. Chem. A 2010, 114, 9523. Ghosh, D.; Chen, S.; J. Mater. Chem., 2008, 18, 755.
4
Tetrahedron 15. (a) Forniés, J.; Martín, A.; Martín, L. F.; Menjón, B.; Organometallics 2005, 24, 3539; (b) Strömberg, S.; Svensson, M.; Zetterberg, K.; Organometallics 1997, 16, 3165. 16. Frisch, M. J. et al. Gaussian, Inc.: Wallingford, CT, USA, 2009. 17. (a) Becke, A. D.; Phys. Rev. A 1988, 38, 3098; (b) Stephens, P. J.; Devlin, F. J.; Chabalowski, C. F.; Frisch, M. J.; J. Phys. Chem. 1994, 98, 11623; (c) Lee, C.; Yang, W.; Parr, R. G.; Phys. Rev. B, 1988, 37, 785. 18. (a) Neto, A. C.; Muniz, E. P.; Centoducatte, R.; Jorge, F. E.; J. Mol. Struct. (Theochem), 2005, 718, 219; (b) Camiletti, G. C.; Machado, S. F.; Jorge, F. E.; J. Comp. Chem. 2008, 29, 2434; (c) Barros, C. L.; De Oliveira, P. J. P.; Jorge, F. E.; Neto, A. C.; Campos, M.; Mol. Phys. 2010, 108, 1965; (d) De Berredo, R. C.;
Jorge, F. E.; J. Mol. Struct. (Theochem), 2010, 961, 107; (e) Neto, A.C.; Jorge, F.E.; Chem. Phys. Lett. 2013, 582, 158.
Supplementary Material Supporting information containing the details of the synthesis of new compounds along with their analytical data is available online
Click here to remove instruction text...
5 Highlights The research reported in this article involved a “green” synthesis of diaryl disulfides in moderate to excellent yield under: 1. Solvent free condition 2. In presence of 5 mol% of Pd(CH2PS)2dba. 3. Variety of aryl thiols are converted to corresponding diaryl disulfides. 4. A putative mechanism is proposed with DFT calculations to provide an insight into the catalyst arylthiols.
mediated dimerization of
S0040-4039(16)31730-0 http://dx.doi.org/10.1016/j.tetlet.2016.12.074 TETL 48486
To appear in:
Tetrahedron Letters
Received Date: Revised Date: Accepted Date:
27 November 2016 21 December 2016 23 December 2016
Please cite this article as: Kumar Dutta, P., Majumder, A., Dutta, S., Bijayi Dhar, B., Munshi, P., Sen, S., Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols, Tetrahedron Letters (2016), doi: http://dx.doi.org/10.1016/j.tetlet.2016.12.074
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Graphical Abstract
Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols
Leave this area blank for abstract info.
Pratip Kumar Dutta,1, § Arpi Majumder,2, § Sanjay Dutta,1 Basab Bijayi Dhar,1 Parthapratim Munshi1 and Subhabrata Sen*, 1
1
Tetrahedron Letters
Solvent free, palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols Pratip Kumar Dutta,1, § Arpi Majumder,2, § Sanjay Dutta,1 Basab Bijayi Dhar,1 Parthapratim Munshi1 and Subhabrata Sen*, 1 a
Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Dadri, Chithera, Gautam Budh Nagar, Uttar Pradesh 201314, India LNM Institute of Information Technology, Jaipur - 302 031, India § Equal contributors b
A RT I C L E I N F O
A BS T RA C T
Article history: Received Received in revised form Accepted Available online
An efficient solvent free Pd(PCH2S)2dba catalyzed green-chemical strategy for the synthesis of diaryl disulfides from aryl thiols in moderate to excellent yield is reported. Variety of diaryl disulfides were synthesized. The catalyst is recyclable up to four cycles. 2009 Elsevier Ltd. All rights reserved .
Keywords: Diaryl disulphides Aryl thiol Pd(PCH2S)2dba Green Chemistry DFT calculations
1. Introduction Diaryl disulfide moieties are extremely important as they have multifaceted applications in pharmaceutical industry as well as in the field of material science.1 They are used as novel stabilizer for the tumor suppressor Pdcd4, they are applied to solve sulfur deposition problems in sour gas fields, facilitate a gamut of addition and exchange reactions and by virtue of the reversibility of S-S bond formation, play an integral role in the synthesis of bioactive compounds.2-5 Interestingly polysulfide compounds are frequently used as polymers in rubber industry. In addition compounds with disulfide linkages are used to design lithium ion batteries.6 Due to all these special characteristics and applications, diaryl disulfides are extremely coveted targets for synthesis. Among the strategies used for the synthesis of diaryl disulfides, base mediated oxidation of thiols in presence of a variety of metal oxidants is most commonly harnessed.7 However, effectiveness of this strategy is lessened due to the usage of expensive and toxic reagents and long reaction times. Very recently Carril et al. reported a base mediated metal free aqueous synthesis of diaryl disulfides.8 Stoichiometric triphenyl phosphines are also used to couple arylsulphonates to generate diaryl disulfides at ambient temperature.9 Firouzabadi et al. have also reported a one-pot synthesis of diaryl disulfides with carbon disulfide (CS2) as a sulfur surrogate, with diethylamine and catalytic copper iodide (CuI) in PEG200.10 Keeping in mind the industrial utility of diaryl disulfides and their applications as diverse building blocks, generating a green
chemical strategy for the synthesis of these compounds is an attractive proposition. In this regard, a metal catalyzed, solvent free protocol for the synthesis of these compounds is highly desirable. Here in we report a Pd(PCH2S)2dba catalyzed, solvent free synthesis of diaryl disulfides from the corresponding aryl thiols in moderate to good yields. 2. Results and discussions The catalyst Pd(PCH2S)2dba was discovered by Aizawa et al. It has demonstrated remarkable efficiency in cesium carbonate mediated C-N and C-O bond forming reactions.11-12 To further investigate the utility of this catalyst in the coupling of arylthiols optimization study involving reaction of 1 with 5 mol% of the catalyst in variety of solvents and bases (Table S1, supplementary information) resulted in providing compound 2a under a solvent free reaction condition as depicted in Scheme 1 below.
Scheme 1. Optimization reaction of 2a
2
Tetrahedron
Next we investigated the robustness of this protocol by reacting variety of aryl thiophenols under the optimized condition. From various diaryl disulfides 2a-k, synthesized we could observe that aryl thiols with electron donating substituents are more amenable towards the optimized condition, as they were synthesized in higher yields compared to the electron withdrawing analogs. The position of the functionalities at ortho, meta or para on aryl thiol impart some influence in the reaction as observed in the formation of bromo analogs 2b and 2g (Scheme 2). Interestingly the yield of o, m and p-methoxy
derivatives 2f, i and j was not influenced with the orientation of the methoxy funcationalty (Scheme 2). There was no reaction for the aliphatic thiols and the only heteroaromatic thiol 2k was synthesized in poor yields (25%) (Scheme 2). The compounds were characterized by 1H/ 13C-NMR and high resolution mass spectroscopy. The structure of the final products was confirmed by the representative single crystal X-ray crystallography of compound 2a and was corroborated with the latest reported structure in the chemical crystallographic database (CCDC# 722274).13
Scheme 2. Variety of analogs of diaryl dithiols via the optimized procedure The tentative mechanism of dimerization of aryl thiols is depicted in Scheme 3. We envision consecutive oxidative addition of aryl thiols onto Pd(PCH2S)2dba that may lead to the formation of intermediate B which then undergoes reductive elimination through intermediate C to generate the desired diaryl disulfides 2a-k along with the catalyst (Scheme 1). We assume that higher Pd-S bond energy (~91 kcal mol-1) over Pd-alkene bond energy (~19 kcal mol-1) thermodynamically initiates the catalytic process.14-15 Two Pd-S bonds are formed consecutively that led to the formation of a three membered transition state. To support the proposed catalytic cycle, no product formation was observed with pyridine 2-thiol (a chelating ligand). This may be because the chelating nature of pyridine 2-thiol, prevents simultaneous attack of two thiol moieties on the Pd center to form three membered transition state. Interestingly for pyridine 3-thiol, the desired product 2k was obtained in ~25% yield. This is because the chelation may be less favorable due to longer distance between pyridinic-nitrogen and the thiol moiety.
Scheme 3. Outline of the proposed catalytic cycle for dimerization reaction. To support our putative mechanism, we wanted to investigate the stability of the proposed transition state C (Scheme 1).
3 Accordingly, we performed DFT calculation using Gaussian09 and optimized the structure using B3LYP functional and DZP basis set.16-18 To our utmost gratification, the structure of C was found to be stable as shown in Figure 1. Further, to assess the stability of C, the structure was optimized by performing TDDFT calculation using the same level of theory (C˝). Although the excited state structures C´ and C˝ (Figure 1) underwent some conformational changes but the coordination of Pd-atom with the four S-atoms and the other bond connectivity remained unchanged. The corresponding energy of the excited state of the structure was estimated to be -8681.972 Hartree.
3. Conclusions To summarize we have reported a “green” synthesis of diaryl disulfides from aryl thiols in moderate to good yield. A solvent free protocol with relatively inexpensive thiols as substrates and Pd(PCH2S)2dba as catalyst provides a highly feasible methodology. The products are purified by column chromatography. The catalyst is recyclable to nearly four cycles. The proposed mechanism with DFT calculation tried to provide an insight into the catalyst mediated dimerization of the thiophenols. Efforts are in progress to simplify the purification process through extraction and precipitation so that it will have an overall appeal in the industry. 4. Acknowledgments This research was supported by Shiv Nadar University and Department of Science and Technology. AM is thankful to Department of Science and Technology (DST), Govt. of India for awarding WOS-A fellowship (SR/WOS-A/CS-29/2010). AM expresses her heartiest gratitude to Prof. S. Aizawa, Graduate School of Science and Engineering, University of Toyama, Japan for his guidance in the preparation of the catalysts during her post-doc tenure in his lab. She is also grateful to Dr. Ragini Gupta, Department of Chemistry, Malaviya National Institute of Technology, JLN Marg, Jaipur 302 017, India for being the mentor in the Department of Science and Technology project.
Figure 1. Optimized structure of C using DFT (C´) and TDDFT (C˝) In order to assess the economic viability of the catalyst, we aimed at reusability of Pd(PCH2S)2dba catalyst for dimerization reaction. As shown in Fig. 2, catalyst was recycled for the dimerization of thiophenyl in acetonitrile. The %ge yield depicted in the figure is the isolated yield of the product after each cycle. The catalyst exhibited very good activity for the first two consecutive recycles and modest decrease in conversion was observed during third and fourth cycle. In the fifth cycle however the catalyst activity was nearly half of the first cycle. The decrease in yield since third cycle may be because of loss of catalyst due to handling. The leaching of palladium in solution was checked by ICP-AES analysis of the reaction mixture that indicated palladium content below detectable level (0.01 ppm), which revealed no significant leaching of palladium catalyst.
References and notes 1.
2.
3. 4. 5. 6. 7.
8.
9. 10. 11. 12.
Figure 2. Recyclability study of Pd(PCH2S)2dba catalyst in aqueous medium.
13. 14.
(a) Arisawa, M.; Fujimoto, K.; Morinaka, S.; Yamaguchi, M.; J. Am. Chem. Soc. 2005, 127, 12226; (b) Nishiyama, Y.; Kawamatsu, H; Sonoda, N.; J. Org. Chem. 2005, 70, 2551. (c) Ferris, K. F.; Franz, J. A.; J. Org. Chem. 1992, 57, 777; (d) Antebi, S.; Alper, H.; Tetrahedron Lett. 1985, 26, 2609; (e) Ogawa, A.; Nishiyama, Y.; Kambe, N.; Murai, S.; Sonoda, N.; Tetrahedron Lett. 1987, 28, 3271; (f) W.; Zaharevitz, D.; Summers, M. F.; Wallqvist, A.; Covell, D. G.; J. Med. Chem. 1996, 39, 3606; (g) Dougherty, G.; Haas, O. J. Am. Chem. Soc. 1937, 59, 2469. Schmid, T.; Blees, J. S.; Bajer, M. M.; Wild, J.; Pescatori, L.; Crucitti, G. C.; Scipione, L.; Costi, R.; Henrich, C. J.; Brüne, B.; Colburn, N. H.; Di Santo, R.; PLoS One 2016, 11, e0151643. Voorhees, R. J.; Thomas, E. R.; Kennelley, K. J.; Oil and Gas Journal 1991, 89, 85. Tanaka, K.; Ajiki, K. A.; Tetrahedron Lett. 2004, 45, 5677. (a) Kondo, T.; Mitsudo, T. –A.; Chem. Rev., 2000, 100, 3205; (b) Kumar, S.; Engman, L.; J. Org. Chem., 2006, 71, 5400. Maddanimath, T.; Khollam, Y. B.; Aslam, M.; Mulla, I. S.; Vijayamohanan, K.; J. Power Sources, 2003, 124, 133. (a) Karami, B.; Montazerozohori, M.; Habibi, M. H.; Molecules, 2005, 10, 1358; (b) Iranpoor, N.; Zeynizadeh, B.; Synthesis, 1999, 49; (c) Chauhan, S. M. S.; Kumar, A.; Srinivas, K. A.; Chem. Commun., 2003, 2348; (d) Patel, S.; Mishra, B. K.; Tetrahedron Lett., 2004, 45, 1371; (e) Arisawa, M.; Sugata, C.; Yamaguchi, M.; Tetrahedron Lett., 2005, 46, 6097; (f) Cochran, J. C.; Friedman, S. R.; Frazier, J. P.; J. Org. Chem. 1996, 61, 1533. (a) Carril, M.; SanMartin, R.; Domínguez, E.; Tellitu, I.; Green Chemistry, 2007, 9, 315; (b) Nӧel, T.; Talla, A.; Driessen, B.; Straathof, N. J. W.; Milroy, L. Brunsveld, L.; Hessel, V.; Advance synthesis and Catalysis,2015, 135, 2180. Kabalka, G. W.; Reddy, M. S.; Yao, M. –L.; Tetrahedron Lett. 2009, 50, 7340. Firouzabadi, H.; Iranpoor, N.; Samadi, A.; Tetrahedron Lett. 2014, 55, 1212. Aizawa, S.-H.; Mazumder, A.; Yokohama, Y.; Tamai, M.; Maeda. D.; Kitamura, A.; Organometallics, 2009, 28, 6067. Mazumder, A.; Gupta, R.; Mandal, M.; Babu, M.; Chakraborty, D.; Journal of Organometallic Chemistry, 2015, 781, 23. Mijoviloch, A.; Pettersson, L. G.; de Groot. F. M.; Weckhuysen, B. M.; J. Phys. Chem. A 2010, 114, 9523. Ghosh, D.; Chen, S.; J. Mater. Chem., 2008, 18, 755.
4
Tetrahedron 15. (a) Forniés, J.; Martín, A.; Martín, L. F.; Menjón, B.; Organometallics 2005, 24, 3539; (b) Strömberg, S.; Svensson, M.; Zetterberg, K.; Organometallics 1997, 16, 3165. 16. Frisch, M. J. et al. Gaussian, Inc.: Wallingford, CT, USA, 2009. 17. (a) Becke, A. D.; Phys. Rev. A 1988, 38, 3098; (b) Stephens, P. J.; Devlin, F. J.; Chabalowski, C. F.; Frisch, M. J.; J. Phys. Chem. 1994, 98, 11623; (c) Lee, C.; Yang, W.; Parr, R. G.; Phys. Rev. B, 1988, 37, 785. 18. (a) Neto, A. C.; Muniz, E. P.; Centoducatte, R.; Jorge, F. E.; J. Mol. Struct. (Theochem), 2005, 718, 219; (b) Camiletti, G. C.; Machado, S. F.; Jorge, F. E.; J. Comp. Chem. 2008, 29, 2434; (c) Barros, C. L.; De Oliveira, P. J. P.; Jorge, F. E.; Neto, A. C.; Campos, M.; Mol. Phys. 2010, 108, 1965; (d) De Berredo, R. C.;
Jorge, F. E.; J. Mol. Struct. (Theochem), 2010, 961, 107; (e) Neto, A.C.; Jorge, F.E.; Chem. Phys. Lett. 2013, 582, 158.
Supplementary Material Supporting information containing the details of the synthesis of new compounds along with their analytical data is available online
Click here to remove instruction text...
5 Highlights The research reported in this article involved a “green” synthesis of diaryl disulfides in moderate to excellent yield under: 1. Solvent free condition 2. In presence of 5 mol% of Pd(CH2PS)2dba. 3. Variety of aryl thiols are converted to corresponding diaryl disulfides. 4. A putative mechanism is proposed with DFT calculations to provide an insight into the catalyst arylthiols.
mediated dimerization of