Chiral Squaramide-Catalyzed Enantioselective Conjugate Michael Addition of Various Thiols to α,β-Unsaturated N-Acylated Oxazolidin-2-ones
作者:Le Dai、Hongjun Yang、Fener Chen
DOI:10.1002/ejoc.201100403
日期:2011.9
A highly enantioselective sulfa-Michael addition (SMA) of variousthiols to α,β-unsaturatedN-acylated oxazolidinones has been achieved with a chiral squaramide catalyst under very mild reaction conditions. In addition, the conversion of the β-thio-substituted adduct to the corresponding methyl β-tosylbutanoate was demonstrated in high yield through a methanolysis/oxidation sequence.
A convenient Fe(OTf)2-catalyzed Michael additionreaction of thiols to α,β-unsaturated carbonyl compounds was developed. The use of a simple procedure (EtOH, room temperature, air atmosphere) allowed to set up effective green catalytic conditions for the C–S bond formation. The scope of the reaction was demonstrated using various substituted thiols and original Michael acceptors. The corresponding
Catalytic Asymmetric Conjugate Addition of Simple Alkyl Thiols to α,β-Unsaturated <i>N</i>-Acylated Oxazolidin-2-ones with Bifunctional Catalysts
作者:Yan Liu、Bingfeng Sun、Baomin Wang、Matthew Wakem、Li Deng
DOI:10.1021/ja8085092
日期:2009.1.21
In this communication, we describe an unprecedented highly enantioselective catalytic conjugateaddition of simple alkyl thiols to alpha,beta-unsaturated N-acylatedoxazolidin-2-ones catalyzed by acid-base bifunctional catalysis. This reaction provides a useful catalytic method for the synthesis of optically active chiral sulfur compounds that are otherwise difficult to prepare by asymmetric catalysis