title: Phosphahelicenes in asymmetric organocatalysis: [3+2] cyclizations of γ-substituted allenes and electron-poor olefins.
abstract: The first use of phosphahelicene in enantioselective organocatalysis is reported. New chiral phosphahelicenes have been prepared and enable highly enantioselective [3+2] cyclization reactions between arylidene- or alkylidenemalononitriles and γ-substituted allenoates or cyanoallenes. These reactions afford cyclopentene derivatives in both high yields and diastereoselectivities, with enantiomeric excesses of up to 97 %.
authors.affiliation: Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Sud, 91198 Gif-sur-Yvette (France).
authors.forename: Maxime
authors.initials: M
authors.lastname: Gicquel
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Paul
authors.initials: P
authors.lastname: Aillard
authors.forename: Pascal
authors.initials: P
authors.lastname: Retailleau
authors.forename: Arnaud
authors.initials: A
authors.lastname: Voituriez
authors.forename: Angela
authors.initials: A
authors.lastname: Marinetti
keywords: allenoates; cyclizations; enantioselectivity; organocatalysis; phosphahelicene