Organocatalyzed highly stereoselective Michael addition of ketones to alkylidene malonates and nitroolefins using chiral primary-secondary diamine catalysts based on bispidine
based on bispidine have been developed to catalyze the asymmetric Michaeladdition of ketones to alkylidenemalonates and nitroalkenes. The corresponding products were obtained in high yields (up to 99%) with high diastereoselectivities (up to 99:1) and high enantioselectivities (up to 97% ee) under mild conditions using either environmentally benign water as the solvent or no solvent.
An organocatalytic asymmetric Michaeladdition of ketones to alkylidenemalonates has been developed. In the presence of 20 mol % of urea 1a or N-(pyrrolidin-2-ylmethyl)trifluoromethanesulfonamide 1j, the reactions of ketones with alkylidenemalonates afford the desired Michael adducts in moderate to good yields with good to high enantioselectivities under mild conditions.
Highly Enantioselective Michael Addition of Ketone to Alkylidene Malonates Catalyzed by Binaphthyl Sulfonimides in Water
作者:Shengjian Jia、Chunhua Luo、Daming Du
DOI:10.1002/cjoc.201200910
日期:2012.11
Binaphthyl sulfonimides have been developed to catalyze the asymmetric Michaeladdition of ketone to alkylidene malonates, affording the corresponding Michael products in good to high yields (up to 98%) with good to excellent diastereoselectivity (up to 99:1 dr) and enantioselectivity (up to 92% ee) under mild conditions using environmentally benign water as the solvent.
study, stereoselective conjugate addition of ketones to alkylidenemalonates using organocatalyst has been developed. The reaction in the presence of 20 mol% of a novel thiourea‐sulfonamide organocatalyst afforded conjugate adducts in moderate to high yields (up to 81%) under mild reaction conditions. Excellent diastereoselectivity (up to 98:2 dr) and enantioselectivity (up to 88% ee) were achieved.
Enantioselective Organocatalytic Michael Addition of Ketones to Alkylidene Malonates
作者:Siang-En Syu、Chan-Hui Huang、Ko-Wei Chen、Chia-Jui Lee、Utpal Das、Yeong-Jiunn Jang、Wenwei Lin
DOI:10.1002/chir.22055
日期:2012.8
studied for the direct asymmetric Michaeladdition of ketones and alkylidenemalonates. The organocatalyst (S)‐2‐((naphthalen‐2‐ylthio)methyl)pyrrolidine, bearing a pyrrolidine and a sulfide moiety, showed a very high catalytic activity in the absence of additives. The reaction condition is mild, and the Michael adducts were obtained in very good enantioselectivities (up to 96%), diastereoselectivities