SYNTHESIS OF 2-SUBSTITUTED 1,3-CYCLOHEPTANEDIONE VIA A LEWIS ACID MEDIATED RING EXPANSION REACTION

摘要

We have established a new route to provide 2-substituted 1,3-cycloheptanediones via a Lewis acid mediated ring expansion reaction of cyclobutanones as the key step. The ring expansion reactions were mediated by a series of Lewis acids. Among the used Lewis acids, ZnI_2 was the most practical mediator. This route has succeeded in providing the title compounds even on a multi-gram scale. During the research, the Baeyer-Villiger oxidation of the cyclobutanones to obtain the new bicyclic lactones was also examined. The regioselective oxidation was observed in the case of chlorinated cyclobutanones.