Highly Enantioselective Synthesis of Nitrocyclopropanes via Organocatalytic Conjugate Addition of Bromomalonate to α,β-Unsaturated Nitroalkenes
作者:Yi-ning Xuan、Shao-zhen Nie、Li-ting Dong、Jun-min Zhang、Ming Yan
DOI:10.1021/ol900227j
日期:2009.4.2
Highly enantioselectivesynthesis of nitrocyclopropanes was achieved via the organocatalytic conjugate addition of dimethyl bromomalonate to nitroalkenes and the consequent intramolecular cyclopropanation. 6′-Demethyl quinine was found to be the efficient catalyst. Excellent enantioselectivities, diastereoselectivities, and good yields were obtained for a variety of aryl or heteroaryl nitroethylenes
Stereoselective synthesis of functionalised cyclopropanes from nitroalkenes via an organocatalysed Michael-initiated ring-closure approach
作者:Alessio Russo、Alessandra Lattanzi
DOI:10.1016/j.tetasy.2010.04.005
日期:2010.5
Synthetically useful nitrocyclopropanes are easily obtained via Michael addition of dimethyl bromomalonate to nitrostyrenes promoted by commercially available (S)-alpha,alpha-di-beta-naphthlyl-2-pyrrolidinemethanol as the catalyst, followed by DABCO-mediated intramolecular nucleophilic substitution. The functionalised nitrocyclopropanes are obtained in good yield, excellent diastereoselectivity and up to 49% ee. (C) 2010 Elsevier Ltd. All rights reserved.