title: Biomimetic Total Synthesis of Hyperjapones A-E and Hyperjaponols A and C.
abstract: Hyperjapones A-E and hyperjaponols A-C are complex natural products of mixed aromatic polyketide and terpene biosynthetic origin that have recently been isolated from Hypericum japonicum. We have synthesized hyperjapones A-E using a biomimetic, oxidative hetero-Diels-Alder reaction to couple together dearomatized acylphloroglucinol and cyclic terpene natural products. Hyperjapone A is proposed to be the biosynthetic precursor of hyperjaponol C through a sequence of: 1) epoxidation; 2) acid-catalyzed epoxide ring-opening; and 3) a concerted, asynchronous alkene cyclization and 1,2-alkyl shift of a tertiary carbocation. Chemical mimicry of this proposed biosynthetic sequence allowed a concise total synthesis of hyperjaponol C to be completed in which six carbon-carbon bonds, six stereocenters, and three rings were constructed in just four steps.
authors.affiliation: Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Hiu C
authors.initials: HC
authors.lastname: Lam
authors.affiliation: Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia.
authors.forename: Justin T J
authors.initials: JT
authors.lastname: Spence
authors.affiliation: Department of Chemistry, University of Adelaide, Adelaide, SA, 5005, Australia. jonathan.george@adelaide.edu.au.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: George
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry; D020902:Hypericum / Q000737:chemistry*; D008968:Molecular Conformation; D061065:Polyketides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D061065:Polyketides; D013729:Terpenes; C000611016:hyperjapone; C000628153:hyperjaponol A; C000628152:hyperjaponol C
keywords: biomimetic synthesis; carbocation rearrangements; cascade reactions; natural products; terpenoids