Sc(III)-Catalyzed Enantioselective Addition of Thiols to α,β-Unsaturated Ketones in Neutral Water
摘要:
This report concerns Lewis acid catalyzed enantioselective sulfa-Michael addition in neutral water by using a very efficient Sc(OTf)(3)/bipyridine 1 catalytic system. It is noteworthy that the protocol presented employs water as a reaction medium and allows us to obtain very high stereoselectivity and satisfactory yields for beta-keto sulphides deriving from aliphatic thiols. The recovery and reuse of both the aqueous medium and the catalytic system is also reported.
A Bifunctional Cinchona Alkaloid-Squaramide Catalyst for the Highly Enantioselective Conjugate Addition of Thiols to trans-Chalcones
作者:Le Dai、Su-Xi Wang、Fen-Er Chen
DOI:10.1002/adsc.201000334
日期:2010.9.10
A chiral squaramide catalysts‐promoted asymmetric sulfa‐Michael conjugated addition of thiols to trans‐chalcones is presented. Moderate to excellent yields and high enantioselectivities (up to 99% ee) were achieved under mild conditions.
This report concerns Lewis acid catalyzed enantioselective sulfa-Michael addition in neutral water by using a very efficient Sc(OTf)(3)/bipyridine 1 catalytic system. It is noteworthy that the protocol presented employs water as a reaction medium and allows us to obtain very high stereoselectivity and satisfactory yields for beta-keto sulphides deriving from aliphatic thiols. The recovery and reuse of both the aqueous medium and the catalytic system is also reported.