Application of Palladium(0)-Catalyzed Processes to the Synthesis of Oxazole-Containing Partial Ergot Alkaloids

Abstract

Syntheses of the potent 5-HT1A agonists 2 and 3 were accomplished in several steps from the 6-iodo partial ergoline alkaloid 8. Disparate tactics available for construction of differentially substituted oxazoles led to the development of new and general methodology critical to the efficient preparations of 2 and 3. A novel palladium(0)- and copper(I)-cocatalyzed cyanation reaction provided efficient access to the nitrile 10, a key intermediate in the synthesis of 2. A palladium(0)-catalyzed cross-coupling reaction of 16 with oxazol-2-ylzinc chloride formed the potent 5-HT1A agonist 3.