Regioselective Ring-Opening of Oxetanes Catalyzed by Lewis Superacid $\mathrm{Al(C)_{6}F_{5})_{3}}$

Abstract

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 °C, employing 1 mol % of $\mathrm{Al(C)_{6}F_{5})_{3}}$ 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 σ1 receptor agonist RC-33.