Synthesis of 2-acyl benzofurans and indoles based on nucleophile-intercepted Meyer–Schuster rearrangement of o-hydroxyphenyl and o-aminophenyl propargylic alcohols

A new type of nucleophile-intercepted Meyer–Schuster rearrangement mediated by pyridine N-oxide under metal-free conditions using a catalytic amount of acid is disclosed. It enables synthesis of 2-acyl benzofurans and indoles in 56–>99% yields.