Augmentation of Enantioselectivity by Spatial Tuning of Aminocatalyst: Synthesis of 2-Alkyl/aryl-3-nitro-2<i>H</i>-chromenes by Tandem Oxa-Michael–Henry Reaction
作者:Rahul Mohanta、Ghanashyam Bez
DOI:10.1021/acs.joc.9b03366
日期:2020.4.3
The asymmetric oxa-Michael addition of salicylaldehyde to conjugatednitroalkenes often suffers from poor reactivity and selectivity and a long reaction time. Because of the formation of an iminium ion with aminocatalyst, the nucleophilicity of the phenolic hydroxy group in salicylaldehyde reduces further to make the oxa-Michael reaction reversible. Here, we report a structurally simple and easily