Synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans via electrophilic cyclization of o-anisole-substituted ynamides with carbocations.

A facile carbocation-induced electrophilic cyclization reaction has been developed for the synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans from o-anisole-substituted ynamides and diarylmethanol or 1,1-diarylprop-2-yn-1-ol.