Chiral Ammonium Betaines: A Bifunctional Organic Base Catalyst for Asymmetric Mannich-Type Reaction of α-Nitrocarboxylates
作者:Daisuke Uraguchi、Kyohei Koshimoto、Takashi Ooi
DOI:10.1021/ja8041004
日期:2008.8.1
A chiralammoniumbetaine, an intramolecular ion-pairing quaternary ammonium aryloxide 3, has been designed and its vast potential as an enantioselective organic base catalyst has been successfully demonstrated in the highly enantioselective direct Mannich-type reaction of alpha-substituted alpha-nitrocarboxylates 2 with various N-Boc imines 1. The present study provides a conceptually new approach