Flash vacuum pyrolysis of α-acyl-o-methoxybenzylidenetriphenylphosphoranes to give 2-substituted benzofurans

Abstract

The title stabilised ylides, readily prepared in one step from acid chlorides, are converted upon FVP at 850 °C into 2-substituted benzofurans. When the acyl group is aromatic it appears unchanged as the 2- substituent in the product while for aliphatic examples degradation processes may lead to 2-alkenyl products.