Barluenga's reagent with HBF4 as an efficient catalyst for alkyne-carbonyl metathesis of unactivated alkynes

Barluenga's reagent (IPy2BF4, Py = pyridine) treated with HBF4 efficiently catalyzes the inter- and intramolecular alkyne-carbonyl metathesis of unactivated alkynes with aldehydes or ketones, most of which proceed at room temperature. This work represents the first catalytic application of the Barluenga's reagent.