Total Synthesis of Phenanthroindolizidine Alkaloids through an Amidyl Radical Cascade/Rearrangement Reaction

A short and general synthesis of the phenanthroindolizidine alkaloids is reported, featuring an unusual amidyl radical 5-<i>exo</i>/5-<i>exo</i>/rearrangement cascade of a xanthate precursor. Second, using an amidyl radical 5-<i>exo</i>/6-<i>endo</i> cascade to synthesize a phenanthroindolizidine alkaloid exclusively has been developed through a small structural modification