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

Org Biomol Chem. 2017 Jan 18;15(3):680-683. doi: 10.1039/c6ob01884j.

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.