title: Diels-Alder approach for the construction of halogenated, o-nitro biaryl templates and application to the total synthesis of the anti-HIV agent siamenol.
abstract: A rapid Diels-Alder approach to halogenated biaryl templates is described. These biaryl templates are available in two steps from the corresponding aromatic aldehydes. The scope of subsequent Suzuki couplings on the biaryl chlorides is explored. Good tolerance for both electron-donating and electron-withdrawing groups in the coupling process can be achieved. Further functionalization of the biaryl templates is described. Hydrogenation of the nitro moiety with concomitant removal of the benzyl ether yields the o-anilino, o-phenolic polyaryls. Selective reduction of the nitro group can be accomplished. Alternatively, the benzyl ether can be selectively removed under Lewis acidic conditions. The utilization of the Diels-Alder adducts for the synthesis of a series of chlorinated carbazoles via the Cadogan cyclization is also demonstrated. Finally, application of this technology to the total synthesis of siamenol, an anti-HIV agent, is reported.
authors.affiliation: Department of Chemistry, 153 Gilbert Hall, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Naffziger
authors.forename: Bradley O
authors.initials: BO
authors.lastname: Ashburn
authors.forename: Johanna R
authors.initials: JR
authors.lastname: Perkins
authors.forename: Rich G
authors.initials: RG
authors.lastname: Carter
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D019380:Anti-HIV Agents / Q000138:chemical synthesis* / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry*; D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D019380:Anti-HIV Agents; D001713:Biphenyl Compounds; D002227:Carbazoles; D006846:Hydrocarbons, Halogenated; C408013:siamenol