Synthesis of (+)-Lysergol and Its Analogues To Assess Serotonin Receptor Activity.

An efficient synthesis of ergot alkaloid lysergol and its analogues is described, providing compounds for functional evaluation at the human 5-HT1A, 5-HT2A, 5-HT2B, or 5-HT2C receptors. Key features of the synthesis include the development of a tandem reaction to construct the multifunctionalized piperidine skeleton and use of a rhodium-catalyzed [3 + 2] annulation in the late-stage indole formation.