Total synthesis and absolute configuration of liverwort diterpenes, (-)-13(15)E,16E-3beta,4beta-epoxy-18-hydroxysphenoloba-13(15),16-diene and (-)-13(15)Z,16E-3beta,4beta-Epoxy-18-hydroxysphenoloba-13(15),16-diene, by use of the ring closing metathesis reaction applied to seven-membered carbocycles with a trisubstituted double bond

Katsuyuki Nakashima; Kosuke Inoue; Masakazu Sono; Motoo Tori

doi:10.1021/jo020287d

Total synthesis and absolute configuration of liverwort diterpenes, (-)-13(15)E,16E-3beta,4beta-epoxy-18-hydroxysphenoloba-13(15),16-diene and (-)-13(15)Z,16E-3beta,4beta-Epoxy-18-hydroxysphenoloba-13(15),16-diene, by use of the ring closing metathesis reaction applied to seven-membered carbocycles with a trisubstituted double bond

J Org Chem. 2002 Aug 23;67(17):6034-40. doi: 10.1021/jo020287d.

Authors

Katsuyuki Nakashima¹, Kosuke Inoue, Masakazu Sono, Motoo Tori

Affiliation

¹ Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.

PMID: 12182639
DOI: 10.1021/jo020287d

Abstract

Seven-membered cyclic compounds possessing trisubstituted double bonds have been effectively constructed employing the Grubbs catalyst to effect olefin metathesis. The keto ester does not undergo cyclization; however, alcohols protected by the silyl groups smoothly cyclized into seven-membered compounds. The product was successfully converted to (-)-13(15)E,16E-3beta,4beta-epoxy-18-hydroxysphenoloba-13(15),16-diene and (-)-13(15)Z,16E-3beta,4beta-epoxy-18-hydroxysphenoloba-13(15),16-diene, liverwort diterpenes isolated from Anastrophyllum auritum to establish the absolute configuration.