title: Naphthol radical couplings determine structural features and enantiomeric excess of dalesconols in Daldinia eschscholzii.
abstract: Understanding how simple molecules are pieced together in organisms may aid biotechnological manipulation and synthetic approaches to complex natural products. The mantis-associated fungus Daldinia eschscholzii IFB-TL01 produces the unusually structured immunosuppressants (±)-dalesconols A and B, along with their congener (±)-dalesconol C, with the (-)-enantiomers in excess. Here we report that these structural and stereochemical peculiarities of dalesconols A-C are a result of promiscuous and atropselective couplings of radicals derived from 1,3,6,8-tetrahydroxynaphthalene, 1,3,8-trihydroxynaphthalene and 1,8-dihydroxynaphthalene. The observed (-)-enantiomeric excess is found to depend on the dominance of particular conformers of naphthol dimer intermediates, which are ligands of laccase.
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing                 210093, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.forename: Shen
authors.initials: S
authors.lastname: Ji
authors.forename: Nan
authors.initials: N
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Guo Yan
authors.initials: GY
authors.lastname: Zhao
authors.forename: Su
authors.initials: S
authors.lastname: Zhang
authors.forename: Hui Ming
authors.initials: HM
authors.lastname: Ge
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xu
authors.forename: Ai Hua
authors.initials: AH
authors.lastname: Zhang
authors.forename: Ying Lao
authors.initials: YL
authors.lastname: Zhang
authors.forename: Yong Chun
authors.initials: YC
authors.lastname: Song
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Ren Xiang
authors.initials: RX
authors.lastname: Tan
mesh_terms: D003986:Dibenzocycloheptenes / Q000737:chemistry* / Q000378:metabolism; D005609:Free Radicals / Q000737:chemistry* / Q000378:metabolism; D009284:Naphthols / Q000737:chemistry* / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism; D013098:Xylariales / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003986:Dibenzocycloheptenes; D005609:Free Radicals; D009284:Naphthols; D011084:Polycyclic Aromatic Hydrocarbons; C552720:dalesconol A; C552721:dalesconol B; C577900:dalesconol C