Highly Enantioselective 1,4-Michael Additions of Nucleophiles to Unsaturated Aryl Ketones with Organocatalysis by Bifunctional Cinchona Alkaloids
作者:Cristina G. Oliva、Artur M. S. Silva、Diana I. S. P. Resende、Filipe A. A. Paz、José A. S. Cavaleiro
DOI:10.1002/ejoc.201000273
日期:——
The development of general and efficient asymmetric organocatalytic additions of malononitrile and nitromethane to 1,5-diarylpenta-2,4-dien-1-ones (cinnamylideneacetophenones) catalyzed by cinchona organocatalysts is reported. The reactions afforded excellent enantioselectivities (up to 99 %), high yields (up to 97 %), and exclusive 1,4-addition regioselectivities. The potential of these new enantioselective
Highly Enantioselective and Regioselective Conjugate Addition of Nitromethane to 1,5-Diarylpenta-2,4-dien-1-ones Using Bifunctional Cinchona Organocatalysts
A general and efficient asymmetric organocatalytic 1,4-Michael addition of nitromethane to 1,5-diarylpenta-2,4-dien-1-ones (cinnamylideneacetophenones) catalyzed by 9-thiourea-9-(deoxy)-epi-hydroquinine has been developed. The reactions afforded excellent enantioselectivities (up to 99%), high yields (up to 97%), and exclusive regioselectivity.