Total Synthesis of (−)-Chanoclavine I and an Oxygen-Substituted Ergoline Derivative

An efficient and direct route to ergot alkaloid (−)-chanoclavine I (3) is described using the inexpensive compound (2R)-(+)-phenyloxirane (15) as a chiral pool in 13 steps with 17% overall yield. Key features of the synthesis include a palladium-catalyzed intramolecular aminoalkynylation of terminal olefin and a rhodium-catalyzed intramolecular [3 + 2] annulation. An oxygen-substituted ergoline derivative (−)-25 was also achieved by using the same strategy.