Asymmetric alkynylation of aldehydes with propiolates without high reagent loading and any additives.

The asymmetric alkynylation of aliphatic and aromatic aldehydes with propiolates was mediated by dialkylzinc and a novel prolinol catalyst without high reagent loading and any additives, such as Ti(Oi-Pr)(4), to give the corresponding γ-hydroxy-α,β-acetylenic esters with high enantiomeric excess of up to 95%.