Total Synthesis of the Phenylnaphthacenoid Type II Polyketide Antibiotic Formicamycin H via Regioselective Ruthenium-Catalyzed Hydrogen Auto-Transfer [4 + 2] Cycloaddition.

ABSTRACT: The first total synthesis of the pentacyclic phenylnaphthacenoid type II polyketide antibiotic formicamycin H is described. A key feature of the synthesis involves the convergent, regioselective assembly of the tetracyclic core via ruthenium-catalyzed α-ketol-benzocyclobutenone [4 + 2] cycloaddition. Double dehydration of the diol-containing cycloadduct provides an achiral enone, which upon asymmetric nucleophilic epoxidation and further manipulations delivers the penultimate tetracyclic trichloride in enantiomerically enriched form. Subsequent chemo- and atroposelective Suzuki cross-coupling of the tetracyclic trichloride introduces the E-ring to complete the total synthesis. Single-crystal X-ray diffraction analyses of two model compounds suggest that the initially assigned stereochemist

SUBMITTER: Hu G 

PROVIDER: S-EPMC11470536 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature