Sc(OTf)3-Catalyzed Precise Construction of Medium-Sized [4.2.1]-Oxabridged Scaffolds

Abstract

In this study, the readily available and inexpensive Sc(OTf)₃ was utilized to activate ortho-benzoyl diazo compounds to in situ generate highly reactive cyclic 1,3-dipoles, which underwent a regioselective [4 + 3] cycloaddition with dioxopyrrolidines, yielding the [4.2.1]-oxabridged scaffolds bearing multiple contiguous quaternary carbon centers with high diastereoselectivities. The method not only exhibited significant economic and operational advantages but also demonstrated practical value through gram-scale synthesis and derivatization experiments.