Asymmetric Synthesis of Phenanthroindolizidine Alkaloids with Hydroxyl Group at the C14 Position and Evaluation of Their Antitumor Activities.

The asymmetric total synthesis of the strongly cytotoxic phenanthroindolizidine alkaloid (IX) is achieved via a photo-induced electron cyclization reaction to (II), a racemization-free amination—cyclization sequence using (S)-diisopropyl glutamate as chiral building block, and diastereoselective reduction to (VIII).