Central–axial–central chirality transfer: asymmetric synthesis of highly substituted indenes bearing a stereogenic quaternary carbon center from optically active propargyl alcohols

Abstract

An asymmetric synthesis of highly substituted indenes 3, bearing a quaternary stereogenic carbon center, has been developed via the central–axial–central chirality transfer from optically active propargyl alcohols 1. This transformation involves the addition/rearrangement of 1 and ynamides 2 to give tetra-substituted allenes 4 and further cyclization of 4.