The synthesis of chiral β-ketosulfoxides by enantioselective oxidation and their stereocontrolled reduction to β-hydroxysulfoxides
摘要:
Various chiral non-racemic beta-ketosulfoxides, a class of compounds frequently used in asymmetric synthesis, were prepared in good yields by tert-butyl hydroperoxide oxidation of the corresponding sulfides in the presence of a complex between titanium and (S,S)-hydrobenzoin. The ee values of almost all of the purified products were > 98%. As ascertained by X-ray analysis and/or by NMR spectroscopy, the use of the (S,S)-form of the ligand led to aryl beta-ketosulfoxides with (R-S)-configuration and to methyl phenacyl sulfoxide with the (S-S)-configuration. Some of the aryl ketosulfoxides were subjected to reduction with DIBAL-H/ZnCl2 and the corresponding beta-sulfinylalcohols with an (R,R-S)-configuration produced. (c) 2005 Elsevier Ltd. All rights reserved.
A switchable and benign protocol for chemoselectivesynthesis of sulfoxides and α-alkoxy-β-ketothioethers has been developed. It was determined that various thiophenols and alkenes/alkynes are compatible to realize the target compounds from a medium to a high yield by regulating the reaction temperature. In particular, methanol not only served as a solvent but also participated in the reaction process
Pummerer Reaction of Sulfoxides in Acetic Anhydride Catalyzed by Al-MCM-41
作者:Suguru Ito、Yoshihiro Kubota、Masatoshi Asami
DOI:10.1246/cl.150896
日期:2016.1.5
The Pummerer reaction of acetic anhydride with both alkyl aryl sulfoxides and dialkyl sulfoxides was efficiently promoted by a mesoporous aluminosilicate Al-MCM-41 to afford the corresponding α-ace...
The synthesis of chiral β-ketosulfoxides by enantioselective oxidation and their stereocontrolled reduction to β-hydroxysulfoxides
作者:Cosimo Cardellicchio、Omar Hassan Omar、Francesco Naso、Maria Annunziata M. Capozzi、Francesco Capitelli、Valerio Bertolasi
DOI:10.1016/j.tetasy.2005.12.004
日期:2006.1
Various chiral non-racemic beta-ketosulfoxides, a class of compounds frequently used in asymmetric synthesis, were prepared in good yields by tert-butyl hydroperoxide oxidation of the corresponding sulfides in the presence of a complex between titanium and (S,S)-hydrobenzoin. The ee values of almost all of the purified products were > 98%. As ascertained by X-ray analysis and/or by NMR spectroscopy, the use of the (S,S)-form of the ligand led to aryl beta-ketosulfoxides with (R-S)-configuration and to methyl phenacyl sulfoxide with the (S-S)-configuration. Some of the aryl ketosulfoxides were subjected to reduction with DIBAL-H/ZnCl2 and the corresponding beta-sulfinylalcohols with an (R,R-S)-configuration produced. (c) 2005 Elsevier Ltd. All rights reserved.
Tf<sub>2</sub>O-Mediated Direct Synthesis of 4-Sulfenylated Oxazoles from β-Keto Sulfoxides and Nitriles
A general and efficient method for the synthesis of 4-sulfenylated oxazoles is described. Trisubstituted oxazoles are obtained in good to excellent yields from β-keto sulfoxides and nitriles. The mechanistic study suggests that the reaction proceeds via the nucleophilic addition of nitriles to the in situ formed α-carbonyl cation followed by intramolecular cyclization.