posted on 2004-09-30, 00:00authored byBeatriz Iglesias, Agustín Cobas, Dolores Pérez, Enrique Guitián, K. Peter C. Vollhardt
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. Cocylization of 2a,b with dimethyl acetylenedicarboxylate provides the phenanthrene- and naphthalenecarboxylic ester
analogues, depending on the catalyst used.