title: Enantioselective synthesis of pyranonaphthoquinone antibiotics using a CBS reduction/cross-metathesis/oxa-Michael strategy.
abstract: The enantioselective syntheses of deoxydihydrokalafungin (5), cis-deoxydihydrokalafungin (6) and deoxykalafungin (7) are reported. The strategy was based on 4 key reactions: (1) CBS reduction of prochiral ketone 10 to introduce chirality at C-1, (2) radical allylation of quinone 9a, (3) cross-metathesis of dimethoxynaphthalene 13 with methyl acrylate, and (4) intramolecular oxa-Michael addition of alcohol 8 to form the core naphthopyran ring system. This novel approach delivers naphthopyrans possessing the natural trans-stereochemistry observed in the pyranonaphthoquinone family of antibiotics.
authors.affiliation: Department of Chemistry, University of Auckland, 23 Symonds Street, Auckland, 1142, New Zealand.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Hume
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sperry
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Brimble
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000900:Anti-Bacterial Agents; D009285:Naphthoquinones; D011714:Pyrans