title: Modular, Metal-Catalyzed Cycloisomerization Approach to Angularly Fused Polycyclic Aromatic Hydrocarbons and Their Oxidized Derivatives.
abstract: Palladium-catalyzed cross-coupling reactions of 2-bromobenzaldehyde and 6-bromo-2,3-dimethoxybenzaldehyde with 4-methyl-1-naphthaleneboronic acid and acenaphthene-5-boronic acid gave corresponding o-naphthyl benzaldehydes. Corey-Fuchs olefination followed by reaction with n-BuLi led to various 1-(2-ethynylphenyl)naphthalenes. Cycloisomerization of individual 1-(2-ethynylphenyl)naphthalenes to various benzo[c]phenanthrene (BcPh) analogues was accomplished smoothly with catalytic PtCl2 in PhMe. In the case of 4,5-dihydrobenzo[l]acephenanthrylene, oxidation with DDQ gave benzo[l]acephenanthrylene. The dimethoxy-substituted benzo[c]phenanthrenes were demethylated with BBr3 and oxidized to the o-quinones with PDC. Reduction of these quinones with NaBH4 in THF/EtOH in an oxygen atmosphere gave the respective dihydrodiols. Exposure of the dihydrodiols to N-bromoacetamide in THF-H2O led to bromohydrins that were cyclized with Amberlite IRA 400 HO(-) to yield the series 1 diol epoxides. Epoxidation of the dihydrodiols with mCPBA gave the isomeric series 2 diol epoxides. All of the hydrocarbons as well as the methoxy-substituted ones were crystallized and analyzed by X-ray crystallography, and these data are compared to other previously studied BcPh derivatives. The methodology described is highly modular and can be utilized for the synthesis of a wide variety of angularly fused polycyclic aromatic hydrocarbons and their putative metabolites and/or other derivatives.
authors.affiliation: †Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Thomson
authors.affiliation: ‡Naval Research Laboratory, Code 6030, 4555 Overlook Avenue, Washington D.C. 20375, United States.
authors.forename: Damon
authors.initials: D
authors.lastname: Parrish
authors.affiliation: †Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, United States.
authors.forename: Padmanava
authors.initials: P
authors.lastname: Pradhan
authors.affiliation: †Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, New York 10031, United States.
authors.forename: Mahesh K
authors.initials: MK
authors.lastname: Lakshman
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D007536:Isomerism; D009281:Naphthalenes / Q000737:chemistry*; D010084:Oxidation-Reduction; D010616:Phenanthrenes / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C000604288:2-bromobenzaldehyde; C000604319:4-methyl-1-naphthaleneboronic acid; C000604320:6-bromo-2,3-dimethoxybenzaldehyde; D001547:Benzaldehydes; D001897:Boronic Acids; D009281:Naphthalenes; D010616:Phenanthrenes; D011084:Polycyclic Aromatic Hydrocarbons