Vilsmeier-Type Reaction of Dimethylaminoalkenoyl Cyclopropanes: One-Pot Access to 2,3-Dihydrofuro [3,2-<i>c</i>]pyridin-4(5<i>H</i>)-ones

Abstract

A domino reaction of readily available 1-carbamoyl-1-dimethylaminoalkenoylcyclopropanes in the presence of triflic anhydride (Tf(2)O) in N,N-dimethylformamide (DMF) is described, which provides a facile one-pot access to 2,3-dihydrofuro[3,2-c]pyridin-4(5H)-ones via tandem formylation (Vilsmeier-type reaction), intramolecular cyclization, and ring-enlargement sequences.