The Asymmetric Horner-Wadsworth-Emmons Reaction Mediated by An External Chiral Ligand

Abstract

The astonishingly simple chiral ligand 1 was used in the first asymmetric variant of the Horner-Wadsworth-Emmons reaction. The products of olefination of 4-substituted cyclohexanones with lithium phosphanates arise via the resulting hydroxyphosphonates, which are present in high enantiomeric excess (see scheme below). R=aryl, vinyl; R'=Me, tBu, Ph.