title: Tris(benzocyclobutadieno)triphenylene and its lower biphenylene homologues by palladium-catalyzed cyclizations of 2,3-didehydrobiphenylene.
abstract: [reaction: see text] The Pd-catalyzed cycloaddition of didehydrobiphenylenes 2a,b, generated from the corresponding 3-(trimethylsilyl)-2-biphenylenyl triflates with fluoride, furnishes the C3-symmetric trimers 1a,b in which the embedded triphenylene unit is distorted to increase the aromaticity of the central benzene ring. Cocyclization of 2a,b with dimethyl acetylenedicarboxylate provides the phenanthrene- and naphthalenecarboxylic ester analogues, depending on the catalyst used.
authors.affiliation: Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Iglesias
authors.forename: Agustín
authors.initials: A
authors.lastname: Cobas
authors.forename: Dolores
authors.initials: D
authors.lastname: Pérez
authors.forename: Enrique
authors.initials: E
authors.lastname: Guitián
authors.forename: K Peter C
authors.initials: KP
authors.lastname: Vollhardt