Total Syntheses of Marrubiin and Related Labdane Diterpene Lactones

• Published in: Molecules (Basel, Switzerland) Vol. 25; no. 7; p. 1610
• Main Authors: Sakagami, Yukari, Kondo, Naoki, Sawayama, Yuki, Yamakoshi, Hiroyuki, Nakamura, Seiichi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2020; MDPI
• Subjects: Acids; Activated carbon; Biological Products - chemical synthesis; Biological Products - chemistry; Chemistry Techniques, Synthetic; chiral building block; Decalin; Diterpenes; Diterpenes - chemical synthesis; Diterpenes - chemistry; Elongation; Functional groups; labdane; Lactones; Lactones - chemical synthesis; marrubiin; Molecular Structure; Natural products; Pauson-Khand reaction; Stereoisomerism; Stereoselectivity; terpenoid; total synthesis; Pauson-Khand reaction; labdane; chiral building block; terpenoid; total synthesis; marrubiin
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25071610

Total syntheses of the labdane diterpene lactones marrubiin, marrulibacetal, desertine, marrulibacetal A, marrubasch F, cyllenine C, marrulanic acid, and marrulactone are described. The -decalin moiety of these molecules was constructed in a stereoselective manner by a Pauson-Khand reaction, and the resultant cyclopentenone was oxidatively cleaved for formation of the lactone ring. Elongation of the side chain at C9 was achieved by an epoxide-opening reaction with a variety of nucleophiles, and the functional group manipulations completed the syntheses of these natural products. Stereochemistries of desertine could be established by the transformations.