Rhodium-Catalyzed Oxidative Synthesis of Quinoline-Fused Sydnones via 2-fold C-H Bond Activation.

Rh(III)-catalyzed synthesis of mesoionic heterocycles has been achieved via C-H activation of sydnones and oxidative coupling with internal alkynes. This reaction occurred under mild conditions with high efficiency, broad substrate scope, and low catalyst loading. Moreover, synthetic applications of a coupled product have been demonstrated in the late-stage derivatization into a variety of highly functionalized scaffolds.