Development of a Scalable Synthetic Route to BMS-986251. Part 1: Synthesis of the Cyclohexane Dicarboxylate Fragment

The cyclohexane dicarboxylate unit of BMS-986251 (1), a potent and efficacious RORγt inverse agonist, was synthesized starting from Hagemann’s ester in seven chemical transformations with five isolated intermediates. The synthesis involved an enzymatic kinetic resolution, a two-step telescoped enol tosylation followed by carboxylation using a benign CO surrogate for the installation of the second carboxylate functionality, and a Crabtree catalyst-mediated diastereoselective olefin hydrogenation. This process was successfully demonstrated to produce 3.6 kg of compound 3.