Organocatalytic Asymmetric Synthesis of Functionalized 4H-Chromenes via a One-Pot Domino Michael-Hemiacetalization and Dehydration Sequence
作者:Dieter Enders、Gregor Urbanietz、Gerhard Raabe
DOI:10.1055/s-0030-1260017
日期:2011.6
A one-pot thiourea-catalyzedenantioselectivesynthesis of polyfunctionalized 4H-chromenes via a domino Michael-hemiacetalization reaction and subsequent dehydration is reported. Starting from 2-nitrovinylphenols and β-keto esters, the new protocol affords the 4H-chromenes bearing a variety of functional groups with good to excellent yields (76-95%) and enantioselectivities ranging from 30-99% ee.