Boronic Acid Catalyzed Rearrangements

Significance

The boronic acid catalyzed 1,3-transposition of allylic alcohols and the Meyer-Schuster rearrangement of propargylic alcohols are reported. Under the influence of electron-poor, polyfluorinated, aromatic boronic acids, a wide range of differently functionalized substrates were transformed to the corresponding products. Mechanistic investigations, featuring oxygen-­labeling experiments shed some light on the activation mode. Whereas the transposition of allylic alcohols seems to proceed via an S_N2′-type mechanism, the Meyer-Schuster rearrangements most likely proceed in an S_N1′-type fashion.