Oxidative Fragmentation of the Bridged β‐Triketone Core of Hyperforin

Abstract

The β‐triketone core of the antidepressant phloroglucinol hyperforin (1) undergoes a series of peroxide‐induced oxidative rearrangements leading to compound 5, which is formed by opening of ring A, and compound 6, which is formed by removal of the C‐1 carbonyl bridge. A mechanistic rationale for this process is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Isolation and Structure Elucidation of Hyperibine J [Revised Structure of Adhyperfirin (7‐Deprenyl‐13‐methylhyperforin)]: Synthesis of Hyperibone J

“…[10,11] Had the original assignment been correct, compound 4 should have been observed; otherwise, compound 5 would be formed (Scheme 1). [10,11] Had the original assignment been correct, compound 4 should have been observed; otherwise, compound 5 would be formed (Scheme 1).…”

“…To unambiguously confirm the structure of hyperibine J (3), the isolated component was subjected to oxidation with meta-chloroperoxybenzoic acid (mCPBA). [10,11] Had the original assignment been correct, compound 4 should have been observed; otherwise, compound 5 would be formed (Scheme 1).…”

Modulation of Chemoselectivity by Protein Additives. Remarkable Effects in the Oxidation of Hyperforin

“…In a previous investigation, we reported that hyperforin reacts with hydrogen peroxide to afford different compounds depending on the oxidation conditions and the stoichiometry of oxidant employed . The hemiacetal ( 2 ) was the major oxidation product, accompanied by a constellation of minor compounds that included various furohyperforins ( 3a − e ) as well as compounds 4 and 5 (Figure ) .…”

“…In a previous investigation, we reported that hyperforin reacts with hydrogen peroxide to afford different compounds depending on the oxidation conditions and the stoichiometry of oxidant employed . The hemiacetal ( 2 ) was the major oxidation product, accompanied by a constellation of minor compounds that included various furohyperforins ( 3a − e ) as well as compounds 4 and 5 (Figure ) . Whereas 2 , 4 , and 5 are products of enol oxidation, furohyperforin is the result of the intramolecular nucleophilic opening of prenol epoxides by the enolic hydroxyl, a process that stabilizes the phloroglucinol core toward oxidative modification.…”

New Acylphloroglucinol Derivatives with Diverse Architectures from Hypericum henryi

“…The structure of hyphenrone D ( 4 ), featuring an unprecedented 6/6/5/8/5 fused ring system, was presumbly formed via an intermolecular Diels–Alder cycloaddition of 2 . In addition, the known hyphenrone F ( 6 ), possessing a 9-nor-PPAP skeleton, may be derived from 1 via sequential hydrolysis and decarboxylation steps . Therefore, the four architectures of these PPAPs are explicable in terms of their presumed biosynthetic origins, and their absolute configurations should accordingly be interrelated.…”