Chiral Brønsted Acid Catalyzed Enantioselective Propargylation of Aldehydes with Allenylboronate

A highly enantioselective chiral Bronsted acid catalyzed propargylation of aldehydes with allenylboronate is described. The reaction is shown to be practical and quite general with a broad substrate scope covering aryl, polyaryl, heteroaryl, α,β-unsaturated, and aliphatic aldehydes.