Enantioselective Synthesis of Natural Epoxyquinoids

Abstract

Natural products play an important role as a source not only of potential therapeutic drugs but also of starting materials for semisynthetic new medicines. The epoxyquinoid family, composed by cyclohexane epoxides and related structures, exhibit these characteristics without doubt.Since 2004, significant efforts have been devoted to the stereocontrolled synthesis of these molecules with different and interesting strategies. More than 50 works on this field have been published during this period of time. In addition, many of these polyoxygenated cyclohexenoids exhibit diverse and impressive bioactive shapes. This review aims to analyze the recent advances in the enantioselective processes that have been performed for the total syntheses of these target molecules. It includes a wide range of methodologies for the introduction of chirality either enzymatic or chemical ones. This summarizes microbial preparation of starting materials, lipase kinetic resolutions, use of compounds from the chiral pool, use of chiral auxiliaries and asymmetric catalysis. In a special section, syntheses of scyphostatin are also included.

A Chemoenzymatic Formal Synthesis of Epoxyquinols A and B

“…Enzymatically derived cis-dihydro diols have been increasingly utilized by organic chemists in syntheses of natural products, including a number of epoxyquinoids. 3,4,[26][27][28] Here we report the chemoenzymatic formal synthesis of epoxyquinols A (1) and B (2) through the preparation of the disilylated enone 4. 25 In this new asymmetric approach to the core of this family of epoxyquinols, chirality is derived from a biocatalytic ipso,ortho cis-dihydroxylation of benzoic acid.…”

Crystal structure and absolute configuration of (3aS,4S,5R,7aR)-2,2,7-trimethyl-3a,4,5,7a-tetrahydro-1,3-benzodioxole-4,5-diol

“…Compounds containing an epoxycyclohexenone skeleton are very interesting, not only because of their wide spectrum of biological activities, but also because of their synthetically challenging chemical structures (Pandolfi et al, 2013). A biotransformation of toluene leads to a chiral diol (see Fig.…”

Total Synthesis of (+)-Pestalofone A and (+)-Iso-A82775C

“…Natural epoxyquinoids show a broad spectrum of biological activities including antibiotic, antifungal, and antitumoral effects . These structural and pharmacological features have rendered the epoxyquinoids popular targets for total synthesis, and new strategies/reactivities have been developed during these synthetic pursuits. , In 2009, Che and co-workers isolated pestalofone A ( 1 , Figure ) from cultures of the plant endophytic fungus Pestalotiopsis fici . They proposed that pestalofone A ( 1 ) is biosynthesized from two units of prenoids and a polyketide.…”