Rh-Catalyzed Formal [3 + 2] Cycloaddition Reactions with Cyclopropenones via Sequential C-H/C-C Bond Activation.

The utilization of high-valent metal catalysts to promote cycloaddition reactions involving π bonds through C-C bond activation remains challenging. Despite extensive research, the cycloaddition of aldehydes with cyclopropenones catalyzed by metal complexes has not been documented. Herein, we disclose a novel Rh(III)-catalyzed cycloaddition reaction between cyclopropenones and aldehydes, enabling the efficient synthesis of highly functionalized furanones.