Stereospecific Synthesis of Allenes from β‐Ketosulfones

Abstract

Enolates formed from 1‐phenyl‐5‐tetrazolyl β‐ketosulfones containing a tetrasubstituted α carbon centre undergo elimination to allenes with up to four substituents at the cumulene unit when treated with a weak base (phenolate) in DMSO at room temperature. The reaction is completely regioselective for allene vs diene formation in nearly all investigated cases and it proceeds with central‐to‐axial chirality transfer.