Heliojatrones A and B, Two Jatrophane-Derived Diterpenoids with a 5/10 Fused-Ring Skeleton from Euphorbia helioscopia: Structural Elucidation and Biomimetic Conversion

• Published in: Organic letters Vol. 20; no. 10; pp. 3124 - 3127
• Main Authors: Mai, Zhen-Peng, Ni, Gang, Liu, Yan-Fei, Li, Li, Li, Jia-Yuan, Yu, De-Quan
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 18.05.2018; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/acs.orglett.8b01215

Heliojatrones A and B (1 and 2), two jatrophane-derived diterpenoids with an unprecedented trans-bicyclo­[8.3.0]­tridecane core, were isolated from the whole plants of Euphorbia helioscopia. Their structures and absolute configurations were unequivocally determined by a combination of spectroscopic data, electronic circular dichroism calculations, biomimetic conversion, and X-ray diffraction analyses. Their plausible biosynthetic pathways were also proposed. Compounds 1 and 2 were biomimetically synthesized from 3 and 4 through a photochemical rearrangement reaction of β,γ-unsaturated ketone, respectively. Compound 2 showed significant P-glycoprotein inhibitory activity compared with the positive control (cyclosporine A).