Catalyst control over pentavalent stereocentres.

Abstract

A monumental diversity of catalytic methods imparts the ability to select one of two configurations of tetravalent stereocentres. Conversely, catalyst control over pentavalent stereocentres, where a fifth moiety bound to the central atom encodes an expanded stereochemical space, remained a challenge to be accomplished. Herein, we report the feasibility of the catalytic tractability of pentavalent stereocentres. A bifunctional iminophosphorane thiourea catalyst enables enantio- and diastereocontrol over pentavalent phosphoranes to differentiate configurationally stable enantiomers and ensembles of diastereomers which emerge together from a single stereocentre. The desired dioxophosphorane stereoisomers are obtained with excellent yield and selectivity (up to 99% yield, 96:4 e.r. and 99:1 d.r.), while stereodivergent catalysis reroutes the reaction for selective access to each of the viable stereoisomeric states of pentavalent phosphoranes. Considering the diversity of high-valent main group species, it is expected that catalyst control over pentavalent stereocentres significantly increases the synthetically addressable stereochemical space.