Regioselective Ring-Opening of Oxetanes Catalyzed by Lewis Superacid Al(C6F5)3

This study details an aluminum-catalyzed regioselective isomerization of 2,2-disubstituted oxetanes to yield homoallylic alcohols. The reaction takes place in toluene at 40( degrees)C, employing 1 mol % of Al(C6F5)(3) as catalyst. This catalytic system shows a wide substrate scope (12 examples). The optimized conditions are especially useful for electron-rich aryl oxetanes, completely suppressing the formation of allyl isomers and reducing the amount of the dimer by-product. The synthetic applicability of the reported methodology is demonstrated by the enantioselective formal synthesis of curcuquinone and the sigma 1 receptor agonist RC-33.