A novel approach to oxazole-containing diterpenoid synthesis from plant roots: salviamines E and F. Issue 3 (21st December 2018)

• Record Type: Journal Article
• Authors: Narita, Koichi; Fujisaki, Narumi; Sakuma, Yuta; Katoh, Tadashi
• Is Part Of: Organic & biomolecular chemistry. Volume 17:Issue 3(2018)
• Page Start: 655
• Page End: 663
• Publication Date: 2018-12-21
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c8ob03030h
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : Salviamines E and F were efficiently synthesized from a known molecule, 5, 7, 8-trimethoxy-1-naphthol. Abstract : In this study, salviamines E and F, which are structurally unique abietane-type diterpene alkaloids containing an oxazole ring, were efficiently synthesized from a known molecule, 5, 7, 8-trimethoxy-1-naphthol. The synthetic sequence involves the following crucial steps: (i) the assembly of a carbon skeleton by coupling a six-carbon homoprenyl unit with a naphthalene moiety (Kumada–Tamao–Corriu coupling); (ii) the construction of a tricyclic phenanthrene ring by acid-induced cyclization of a naphthalene derivative with a homoprenyl side chain; (iii) the formation of an oxazole ring by nucleophilic ring closure of a 2-aminophenylene-1, 4-diyl-diformate or -diacetate moiety and (iv) Friedel–Crafts acetylation at the C13 position of the tetracyclic intermediates to obtain the two target molecules, salviamines E and F. To the best of our knowledge, salviamine synthesis is reported here for the first time.