Strategies for the Total Synthesis of Clavicipitic Acid

Clavicipitic acid is an ergot alkaloid, which was isolated from Claviceps strain and Claviceps fusiformis. Its unique tricyclic azepinoindole skeleton has attracted synthetic chemists, and various strategies have been developed for its total synthesis. These strategies can be generally categorized into two types based on the synthetic intermediates, namely, 4-substituted gramine derivatives and 4-substituted tryptophan derivatives. This Minireview summarizes the reported total syntheses from the point of these two key intermediates Intermediate is key: Clavicipitic acid is an ergot alkaloid with a unique tricyclic azepinoindole skeleton that has attracted many synthetic chemists. This Minireview summarizes the strategies for the total synthesis from the point of two key intermediates.