Direct synthesis of γ-pyrones by electrophilic condensation of β-ketoesters

Abstract

Triflic anhydride is a versatile electrophile that is able to activate poor nucleophiles. Herein, we show that readily available β-keto esters are activated by Tf₂O furnishing γ-pyrones. Mechanistic studies suggest that this transformation proceeds via a double triflation, formation of an oxocarbenium intermediate and dealkylation promoted by a crucial nitrile additive.