Rh(III)-Catalyzed C-H Activation and [4+1+1] Sequential Cyclization Cascade to Give Highly Fused Indano[1,2- b ]azirines.

A Rh(III)-catalyzed C-H activation of α-keto oximes and a cyclization cascade with diazo compounds were developed to construct the highly fused indano[1,2- b ]azirine frameworks in good yields with a broad range of substrates under mild reaction conditions. More intriguingly, a [4+1+1] sequential annulation cascade is demonstrated for the first time in this reaction and opened a new reaction mode for α-keto oximes. These fused indano[1,2- b ]azirine derivatives could also be further transformed into intriguing privileged drug scaffolds.