The P-Chiral Phosphane Ligand (MeO-BIBOP) for Efficient and Practical Large-Scale Rh-Catalyzed Asymmetric Hydrogenation of N-Acetyl Enamides with High TONs

A highly electron-rich P-chiral bis(trialkylphosphane) ligand MeO-BIBOP ( 1 ) was efficiently synthesized on large scale. The MeO-BIBOP–rhodium complex exhibited remarkably high reactivities (up to 200,000 TON) for the hydrogenation of N -acetyl enamides to provide chiral acetamides on kilogram scale. In the meantime, a high-yielding, cost-effective, and practical preparation of N -acetyl enamide by reductive acylation of oxime was developed employing an in situ formation of Fe(II) acetate from Fe/AcOH/Ac 2 O.