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Issue in Honor of Prof. Jan Epsztajn ARKIVOC 2007 (vi) 112-171 Table 2. Representative methods of reduction of sulphoxides to sulphides Meth. R1-S(O)-R2 Reaction Conditions Yields Ref. No R1 R2 Reagents Molar Ratioa Temp. Time (%) (oC) (h) 1 n-Bu n-Bu R1S(O)R2/RSO3H/NaI (1 : 3 : 3) r. t. 0.5 100 29 n-Pr Ph in acetone 1.0 91 Ph Ph 1.0 90 2 i-Pr i-Pr R1S(O)R2/Silica gel/SOCl2 b r. t. 0.2 73 30 Bn Bn 0.2 90 Ph Ph 0.05 81 3 Me Ph R1S(O)R2/Mg/cat. HgCl2 (1 : 4) r. t. 3.0 98 31 in EtOH Ph Ph R1S(O)R2/Mg (1 : 3) -43 3.0 99 in MeOH/THF Bn Ph R1S(O)R2/Mg (1 : 6) -43 5.0 99 in MeOH 4 Me Ph R1S(O)R2/Cp2TiCl2/Sm (1 : 2 : 1) r. t. 1.0 87 32 Ph Ph in THF 82 5 Me Ph R1S(O)R2/TiCl4/Sm (1 : 4 : 2) r. t. 0.5 87 33 Ph Bn in THF 80 Ph Ph 75 6 Met[S(O)] in R1S(O)R2/NH4I (1 : 5-15) 0 0.599 34 peptides in THF 1.0 7 n-Bu n-Bu R1S(O)R2/TsOH/KI (1 : 3 : 3) 30 0.25 73 35 Me Ph in solid state 4.0 97 Ph Ph 4.0 76 8 n-Bu n-Bu R1S(O)R2/Ac2O/DMAP/Zn r. t. 24 81 36 Me Ph (1 : 2 : 0.1 : 10) 12 95 Tol Tol in CH3CN 20 97 9 n-Bu n-Bu R1S(O)R2/DHPy (2: 1) 80 5.0 98 37 Ph Ph in CH3CN 14 24 Bn Bn 4.0 98 10 Me Me R1S(O)R2/WCl6/NaI (1 : 0.5 : 3) r. t. 5.0 98 38 Me Ph in CH3CN 5.0 90 Ph Ph 35 95 11 n-Hex n-Hex R1S(O)R2/TiI4 (2 : 3) 0 0.25 85 39 Bn Bn in CH3CN 85 Ph Ph 93 ISSN 1424-6376 Page 121 ©ARKAT USA, Inc.
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