C3-Symmetrical Cinchonine-Squaramide as New Highly Efficient, and Recyclable Organocatalyst for Enantioselective Michael Addition

• Published in: Advanced synthesis & catalysis Vol. 353; no. 14-15; pp. 2715 - 2720
• Main Authors: Min, Chang, Han, Xin, Liao, Zongquan, Wu, Xiangfei, Zhou, Hai-Bing, Dong, Chune
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2011; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: asymmetric Michael addition; Asymmetry; C3-symmetrical species; Catalysis; catalyst recycling; Catalysts; Catalysts: preparations and properties; Chemistry; cinchonine-squaramide; Esters; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; Michael reaction; Organic chemistry; Precipitation; Preparations and properties; Selectivity; Synthesis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Michael addition; asvmmetric Michael addition: C; catalyst recycling; Alkaloid; Enantioselectivity; Nitrogen heterocycle; Organocatalyst; cinchonine-squaramide; Recycling; symmetrical species
• ISSN: 1615-4150; 1615-4169; 1615-4169
• DOI: 10.1002/adsc.201100066

A novel and recyclable catalyst, a C3‐symmetrical cinchonine‐squaramide, has been developed for the asymmetric Michael addition of 1,3‐dicarbonyl compounds to nitroalkenes. When using only 1 mol% of catalyst 1a for the reaction, high reaction yields with excellent enantioselectivities and diastereoselectivities (up to 96% yield,>99% ee,>99:1 dr) were achieved, in which the results for cyclic keto esters are the best ever achieved. Moreover, 1a can be easily recovered by simple precipitation and was used for six cycles without losing any selectivity and activity.