An amino-assisting [3+2] cycloaddition strategy of nitrile imines generated in situ with o-aminotrifluoroacetophenones under mild conditions has been constructed, in which a variety of 1,3,4-oxadiazolines bearing CF3-quaternary centers can be obtained in good to excellent yields. The MTT assay shows that the resulting 1,3,4-oxadiazoline derivatives could be the potential candidates for the treatments of head and neck cancers.

A phosphine-catalyzed [4+3] annulation between dinucleophilic indole derivatives and Morita−Baylis−Hillman (MBH) carbonates was discovered by using the N1 and N4′ or C4′ nucleophilicities of indole precursors, which provides an efficient and facile access to in-dole-1,2-fused 1,4-diazepinones and azepines in good to high yields in one step, in which indoles act as four atom synthons. Various transformations of products illustrate promising applications of the given protocols.