Acid-Catalyzed Rearrangement of Epoxy Alcohol Derivatives having Electron-Withdrawing Functional Groups and Its Application to Natural Products Syntheses

Abstract

The rearrangements of epoxy alcohol derivatives having electron-withdrawing functional groups such as 2,3-epoxy acylates and 2,3-epoxy sulfonates provide a useful method for synthesizing many kinds of chiral compounds having a chiral quaternary carbon center. Epoxides with 2,3-dialkyl substituents react through cleavage of oxirane ring at the C3-position due to the electron-withdrawing nature of the functional groups. A similar reaction course is observed for epoxides with C3-aryl substituents. On the other hand, the reaction of epoxides with C2-aryl substituents occurs through cleavage of oxirane ring at the C2-position due to the cation-stabilizing ability of the aromatic ring.The methods were successfully applied to the asymmetric formal synthesis of (−)-aphanorphine and total syntheses of (+)-(S)-sporochnol, (−)-α-herbertenol and (−)-herbertenediol.