[Development of environmentally benign transformations via 1,3-transposition of hydroxyl group].

This review article describes our recent efforts to develop environmentally benign transformations of allyl and propargyl alcohols via the 1,3-transposition of their hydroxyl groups using combined catalyst systems. This methodology allows for successful transformation under mild conditions, which has never been achieved using each catalyst. Representative examples of this methodology include the following three reactions. First, the combination of oxo-vanadium compounds and lipases resulted in the dynamic kinetic resolution of racemic allyl alcohols to give optically active allyl esters in high yields. Second, Mo-Au-Ag combination catalysis dramatically accelerated the rearrangement of diverse propargyl alcohols into α,β-unsaturated carbonyl compounds. Finally, the choice of suitable heteropoly acids for the rearrangement of propargyl alcohols led to the selective preparation of both (Z)- and (E)-enones.