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. magnified image