Regioselective Difunctionalization of 2,6-Difluorophenols Triggered by Sigmatropic Dearomatization

Regioselective difunctionalization of 2, 6-difluorophenols with aryl sulfoxides and nucleophiles has been accomplished. The reaction is composed of (1) Pummerer-based [3, 3] sigmatropic dearomatization to generate 2, 4-cyclohexadienone, (2) Michael addition of a nucleophile, and (3) liberation of HF for rearomatization. Besides the [3, 3] rearrangement, [2, 3] sigmatropic rearrangement from sulfonium ylide generated from alkyl sulfoxide promotes the dearomatization, resulting in installation of α-sulfanylalkyl group