Non-Biaryl Atropisomers: New Classes of Chiral Reagents, Auxiliaries, and Ligands?

摘要

While many chemists are familiar with the problems posed by abnormally large barriers to rotation about single bonds when it comes to interpreting NMR spectra, few have sought to make use of these barriers as tools for stereoselective synthesis. A renewal of interest in this prospect followed the remarkable observation by Fuji et al. of stereospecific alkylation of ketone 1. The configuration of the starting material 1 was retained in the product 2 despite the intermediacy of an apparently achiral enolate (Scheme 1).