Complementary Tandem Reaction Manifolds and "Switch Mechanisms" in the Reaction of Epoxides with Selectfluor.

Tandem reactions are highly sought after transformations in organic synthesis as they accomplish multiple steps at once and can serve as golden keys unlocking mechanistic complexities. Reactions that operate through different mechanisms depending on the conditions ("switch mechanisms") are of intense interest to organic chemists as fonts of new reactivity. We report that Selectfluor can catalyze the rearrangement of 1,1-disubstituted epoxides, providing a new approach to benzylic fluorination. These results complement earlier work involving radical-cation-based ring opening of epoxides.