Terminal Olefins to Chromans, Isochromans, and Pyrans via Allylic C–H Oxidation

[Image: see text] The synthesis of chroman, isochroman, and pyran motifs has been accomplished via a combination of Pd(II)/bis-sulfoxide C–H activation and Lewis acid co-catalysis. A wide range of alcohols are found to be competent nucleophiles for the transformation under uniform conditions (catalyst, solvent, temperature). Mechanistic studies suggest that the reaction proceeds via initial C–H activation followed by a novel inner-sphere functionalization pathway. Consistent with this, the reaction shows reactivity trends orthogonal to those of traditional Pd(0)-catalyzed allylic substitutions.