Straightforward Synthesis of Dihydrobenzofurans and Benzofurans from Arynes

Abstract

Synthesis of dihydrobenzofurans was achieved by a route involving the insertion of arynes into formamides followed by trapping with zinc enolates of α-chlorinated methines. Benzofurans were generated from dihydrobenzofurans having a ketone group via the addition of an ethyl anion, the retro-aldol type reaction, and the elimination of an amino group.