Synthesis of Enantioenriched Difluoromethylated Allenes via Copper-Catalyzed Stereospecific Difluoromethylation.

Axially chiral allenes are valuable motifs in natural products and chiral ligands in asymmetric catalysis, yet methods to access enantioenriched difluoromethylated analogues remain undeveloped. Here we report the efficient copper-catalyzed SN2'-type substitution of propargylic alcohol derivatives with Zn(CF₂H)₂(DMPU)₂, to deliver enantioenriched difluoromethylated allenes under mild conditions. This transformation proceeds with high regioselectivity, a broad substrate scope, and operational simplicity, providing a general strategy to construct CF₂H-substituted chiral allenes of potential relevance to drug discovery.