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In contrast to well-known transformations of vinyl azides via azirine intermediates or initiating at the alkene moiety, herein we report a Rh(I)-catalyzed coupling reaction of vinyl azides with isonitriles at the azide moiety to form active vinyl carbodiimide intermediates and following tandem cyclization with unsaturated compounds, such as alkynes and benzynes, to give different classes of azaheterocycles. Mechanistically, controlled experiments and DFT calculations disclose that Rh-nitrene is the vital species in the first coupling step, and the Rh(I) catalyst can also play an important role in the cyclization step of alkynes.

A highly enantioselective cis-hydrogenation of 2,3,4-trisubstituted quinolines has been realized for the first time using chiral borane catalysts generated in situ from chiral dienes. A variety of tetrahydroquinoline derivatives containing three contiguous stereogenic centers were obtained in 76-99% yields with 82-99% ee's.

A facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines is reported. Serving as the widely existed fragments in an array of biological pharmaceuticals, functionalized unsymmetrical ureas were straightforwardly synthesized by using readily available and cheap azides with amines under CO atmosphere, with the extrusion of N2 as the only byproduct. It was found that not only aryl azides but also benzyl and alkyl azides were suited for this methodology. Another feature of this procedure was the employment of a highly efficient palladium charcoal catalytic system.

A self-relay rhodium(I)-catalyzed cyclization of alkyne–azides with two σ-donor/π-acceptor ligands (isonitriles and CO) to form sequentially multiple-fused heterocycle systems via tandem nitrene transformation and aza-Pauson–Khand cyclization has been developed. In this approach, an intriguing chemoselective insertion process of isonitriles superior to CO was observed. This reaction provides an alternative strategy to synthesize functionalized pyrrolo[2,3-b]indole scaffolds.