The implication of phenylacetaldehydes in the diosynthesis of the phenanthroindolizidine alkaloid, tylophorine.

Total Synthesis of Phenanthroindolizidine Alkaloids by Combining Iodoaminocyclization with Free Radical Cyclization

“…Since the first total synthesis of (±)-tylophorine in 1961, continuous efforts have been devoted to the preparation of phenanthroindolizidine alkaloids owing to their potent biological activity and their somewhat low natural abundance . These strategies include intramolecular double Michael reactions, Friedel–Crafts acylation, intramolecular cycloaddition, and biomimetic syntheses …”