Isoxerophilins A and B, two diterpene heterodimers from Isodon xerophilus: structural elucidation and semisynthesis of isoxerophilin analogues

Two unprecedented diterpene heterodimers, isoxerophilins A and B (1 and 2), were isolated from Isodon xerophilus . A bioinspired semisynthesis of ten isoxerophilin analogues was accomplished. Compound 12 exhibited obvious latent tumor immunotherapy activity.