Convergency and Divergency as Strategic Elements in Total Synthesis: The Total Synthesis of (−)-Drupacine and the Formal Total Synthesis of (±)-Cephalotaxine, (−)-Cephalotaxine, and (+)-Cephalotaxine

摘要

A concise route toward the syntheses of (−)-drupacine and (+)- and (−)-cephalotaxine has been developed. The syntheses rely on Pd(II)-catalyzed aerobic oxidative heterocyclization chemistry, which was employed to rapidly construct an important spirocyclic amine intermediate. A dynamic β-elimination/conjugate addition process was strategically applied to complete the first asymmetric total synthesis of (−)-drupacine.