Total synthesis of optically active plagiospirolides A and B: highly stereoselective biomimetic Diels–Alder reaction

Based on biogenetic hypothesis, optically active plagiospirolides A and B (C35-terpenoids) have been synthesized by a Diels–Alder reaction between independently synthesized sesquiterpenoids (diplophyllolide A and diplophyllin) and a 5–8–5-membered tricyclic diterpenic hydrocarbon prepared from a CrCl2-mediated condensate of (3S)-benzyloxyirid-1-en-7-al and (3R)-7-chloroirid-1-ene.