Asymmetric Synthesis of Chiral-at-Iridium Complexes through Pd-Catalyzed Kinetic Resolution

Metal-centered chirality has been recognized for over a century, and chiral-at-metal complexes have been widely applied across various natural science fields. However, the synthesis of these molecules remains constrained. Notably, while asymmetric catalysis has played a crucial role in the production of optically active organic molecules, its application to chiral-at-metal complexes is less straightforward. In this study, we introduce a kinetic resolution strategy employing a Pd-catalyzed asymmetric Suzuki-Miyaura cross-coupling reaction that efficiently produces optically active chiral-at-iridium complexes from racemic mixtures with high selectivity (achieving an s-factor of up to 133). This method enables further synthesis of complexes relevant to metallodrugs and chiral photosensitizers, underscoring the practical utility of our approach. Mechanistic studies suggest that reductive elimination is the turnover-limiting step over the Suzuki-Miyaura cross-coupling.