Total Synthesis of (<i>R</i>)‑Sarkomycin Methyl Ester via Regioselective Intermolecular Pauson–Khand Reaction and Iridium-Catalyzed Asymmetric Isomerization

A new five-step enantioselective synthesis of (<i>R</i>)-sarkomycin methyl ester is described. The cyclopentane scaffold was built by a regioselective intermolecular Pauson–Khand reaction. Enantioselectivity was introduced by a novel Ir-catalyzed isomerization reaction. The last steps involved a catalytic hydrogenation of the exocylic double bond, followed by the deprotection and elimination of the amino group. This route is the shortest enantioselective synthesis of this antibiotic reported to date