Chiral Sterically Congested Phosphane‐Amide Bifunctional Organocatalysts in Asymmetric Aza‐Morita–Baylis–Hillman Reactions of <i>N</i>‐Sulfonated Imines with Methyl and Ethyl Vinyl Ketones

Abstract

Abstract A series of chiral sterically congested phosphane‐amide bifunctional Lewis bases L1 – L3 have been successfully synthesized and their application in asymmetric aza‐Morita–Baylis–Hillman (aza‐MBH) reactions of N ‐sulfonated imines with activated olefins such as methyl and ethyl vinyl ketone has been investigated under mild conditions. The corresponding aza‐MBH adducts can be obtained in good‐to‐excellent yields (up to 98 %) and moderate‐to‐good enantioselectivities (up to 91 or 93 % ee ) in dichloromethane at room temperature (20 °C) with these novel chiral bifunctional phosphane Lewis bases.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)