Acid-Promoted Rearrangement of Cyclic α,β-Epoxy Acylates:  Stereoselective Synthesis of Spirocyclanes and Quaternary Carbon Centers

Abstract

The rearrangement reaction of α,β-epoxy acylates in cyclic systems was studied. The treatment of cis -derivatives with a Lewis acid afforded rearranged products via the regioselective β-cleavage of the oxirane ring due to the electron-withdrawing nature of the acyloxy group, whereas trans -derivatives enhanced the neighboring group participation to yield only a small amount of rearranged products. This rearrangement reaction proved to be useful for the construction of a variety of spirocyclane systems or quaternary carbon centers on rings and could be applied to their syntheses as optically active forms.