Stereocontrolled photodimerization with congested 1,8-bis(4'-anilino)naphthalene templates.
Suzuki cross-coupling of a 1,8-dihalonaphthalene with 4-methoxy-3-methylphenylboronic acid or 4-acetamidophenylboronic acid and subsequent functional group transformation gave 1,8-bis(3'-methyl-4'-anilino)naphthalene, 16, and 1,8-bis(4'-anilino)naphthalene, 21, in 65% and 90% overall yield, respectively. These congested compounds exhibit two cofacial aniline rings that favor a proximate, parallel arrangement of covalently attached cinnamoyl units suitable for stereoselective photodimerization. The [2 + 2]cycloaddition was found to proceed with high yield and exclusive formation of cis,trans,cis-cyclobutane-1,2-dicarboxylic acids. Amide formation with cinnamoyl chloride and template 21 followed by photochemical dimerization and acidic hydrolysis gave β-truxinic acid, 10, in 69% overall yield. Coupling of 21 and (E)-3-(3,4-dimethylphenyl)acrylic acid in the presence of EDC, UV irradiation, and cleavage gave cis,trans,cis-3,4-bis(3,4-dimethylphenyl)cyclobutane-1,2-dicarboxylic acid, 26, in 60% yield. In both cases, the template was quantitatively recovered.
Ghosn
Marwan W
MW
Department of Chemistry, Georgetown University, Washington, DC 20057, USA.
Wolf
Christian
C
D018360:Crystallography, X-Ray; D003500:Cyclization; D019281:Dimerization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009281:Naphthalenes / Q000138:chemical synthesis* / Q000737:chemistry; D010777:Photochemistry; D013237:Stereoisomerism
D009281:Naphthalenes