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Biomimetic Total Synthesis of Hyperjapones A–E and Hyperjaponols A and C
Author(s) -
Lam Hiu C.,
Spence Justin T. J.,
George Jonathan H.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201606091
Subject(s) - stereocenter , polyketide , chemistry , carbocation , biomimetic synthesis , stereochemistry , alkene , total synthesis , terpene , epoxide , alkyl , ring (chemistry) , biosynthesis , organic chemistry , enantioselective synthesis , catalysis , enzyme
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.