Chiral squaramide-catalyzed highly diastereo- and enantioselective direct Michael addition of nitroalkanes to nitroalkenes
作者:Wen Yang、Da-Ming Du
DOI:10.1039/c1cc15946a
日期:——
efficient highlydiastereo- and enantioselective direct Michaeladdition of nitroalkanes to nitroalkenes catalyzed by chiral squaramide catalyst has been developed. This organocatalytic reaction with a low catalyst loading (2 mol%) proceeded well to afford synthetically useful 1,3-dinitro compounds in high yields with high diastereoselectivities (up to 95 : 5 dr) and excellent enantioselectivities (up to
Enantioselective Michael reaction of nitroalkanes onto nitroalkenes catalyzed by cinchona alkaloid derivatives
作者:Yan-Qiu Deng、Zhen-Wei Zhang、Ya-Hui Feng、Albert S.C. Chan、Gui Lu
DOI:10.1016/j.tetasy.2012.11.008
日期:2012.12
An effective asymmetric synthesis of optically active 1,3-dinitro compounds via the direct Michael addition of nitroalkanes onto nitroalkenes has been described. In the presence of readily modified cinchona alkaloid derivatives, nitroethane reacted well with a variety of aromatic and heterocyclic aromatic nitroalkenes to afford products with good diastereoselectivities (dr up to 72/28) and enantioselectivities (ee up to 94%). The catalyst loading can be decreased to 2 mol % without compromising the asymmetric induction or the reaction rate. (C) 2012 Elsevier Ltd. All rights reserved.