Old Magician, New Magic: Dirhodium Tetracarboxylates, Unprecedented Bifunctionality in Metallaphotocatalysis

Abstract Metallaphotocatalysis has been recognized as a pivotal catalysis for enabling new reactivities and for expanding chemical space. Traditional metallaphotocatalysis often requires two or more separate catalysts and exhibits flaw in cost and substrate-tolerance, thus representing an await-to-solve issue in catalysis. We herein realize metallaphotocatalysis with a bifunctional dirhodium tetracarboxylate ([Rh2]) alone.The [Rh2] shows an unprecedente photocatalytic activity via a rarely used metal-to-metal transition in photocatalysis. Based on the activity, the [Rh2] connects carbene chemistry and siglet oxygen chemistry to enable a novel photochemical cascde reaction (PCR). The PCR is characterized by high atom-efficiency, excellent stereoselectivities, mild conditions, scalable synthesis, and valuable products. DFT calculations-aided mechanistic study rationalizes the reaction pathway and interprets stereoselectivities of the PCR. The products showed inhibitory activity against PTP1B, being promising in the treatment of type II diabetes and cancers. We believe this work will shed light on discovering bifunctional catalysts for metallaphotocatalysis and on developing PCRs for exploring chemical space.