Efficient and Chirally Specific Synthesis of Phenanthro‐Indolizidine Alkaloids by Parham‐Type Cycloacylation

A concise, efficient and modular route involving Parham‐type cycloacylation as the key step has been used to synthesize six enantiopure phenanthro‐indolizidine alkaloids 1a–c. The preparation of enantiomerically pure tylophora alkaloids and their seco analogues on a large‐scale is now feasible. The alcohol intermediates 8a–c, which are difficult to prepare by other synthetic methodologies, have been synthesized by a metallation–cyclization–reduction sequence in excellent yields.