title: Total synthesis of the marine metabolite (±)-polysiphenol via highly regioselective intramolecular oxidative coupling.
abstract: (±)-Polysiphenol (1), an atropisomerically stable 4,5-dibrominated 9,10-dihydrophenanthrene from Polysiphonia ferulacea, was prepared by a biomimetically inspired highly regioselective intramolecular oxidative coupling of a dibrominated dihydrostilbene. The installation of the two bromine atoms prior to oxidative coupling prevents further oxidation to a planar aromatized phenanthrene. By this strategy, the synthesis of (±)-polysiphenol was achieved in four steps in 70% overall yield. Synthesis of the naturally occurring 5,5'-(ethane-1,2-diyl)bis(3-bromobenzene-1,2-diol) (2) (the likely biogenetic precursor of polysiphenol) and 5,5'-(ethane-1,2-diyl)bis(3,4,6-tribromobenzene-1,2-diol) (9) are also reported. The origins of the regioselectivity in the oxidative coupling are explored.
authors.affiliation: Department of Chemistry, Imperial College London, London, South Kensington SW7 2AZ, UK.
authors.forename: Tim N
authors.initials: TN
authors.lastname: Barrett
authors.forename: D Christopher
authors.initials: DC
authors.lastname: Braddock
authors.forename: Anna
authors.initials: A
authors.lastname: Monta
authors.forename: Michael R
authors.initials: MR
authors.lastname: Webb
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: White
mesh_terms: D001966:Bromine; D006842:Hydrocarbons, Brominated / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D008386:Marine Biology; D015394:Molecular Structure; D058451:Oxidative Coupling; D010616:Phenanthrenes / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D000461:Rhodophyta / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D006842:Hydrocarbons, Brominated; D010616:Phenanthrenes; C562293:polysiphenol; D001966:Bromine