Stereoselective cyclopropanation of α-bromochalcone with diethyl malonate promoted by K2CO3
作者:Yongxian Sun、Gaosheng Yang、Yue Shen、Zan Hua、Zhuo Chai
DOI:10.1016/j.tet.2013.02.011
日期:2013.4
A new Michael-initiated cyclopropanation reaction using alpha-bromochalcones as Michael acceptor was developed. Compared to previous works using arylidenemalonates as Michael acceptor, this novel protocol could improve the synthesis of trans-isomers of diethyl 2-benzoyl-3-phenyl-cyclopropane-1,1-dicarboxylates. More importantly, this method also provided the first access to the cis-isomers of these densely substituted cyclopropanes with the Michael-initiated ring closure (MIRC) strategy, albeit with a poor diastereoselectivity. (C) 2013 Published by Elsevier Ltd.