Metal-free direct C(sp3)−H functionalization of 2-alkylthiobenzoic acid to access 1,3-benzooxathiin-4-one

Abstract Metal-free direct α-C(sp3)−H intramolecular cyclization of 2-alkylthiobenzoic acid in the presence of Selectfluor is described. This novel strategy provides a facile and efficient method to access important 1,3-benzooxathiin-4-one derivatives with good functional groups tolerance and yields.