title: En route to archimedene: total synthesis of C3h-symmetric [7]phenylene.
abstract: [reaction: see text] The total synthesis of C(3)(h)-symmetric [7]phenylene has been accomplished by triple cobalt-catalyzed cycloisomerization of an appropriate nonayne. Its spectral data are in accord with the expectations for a triply angularly fused system, but its calculated heat of formation suggests the presence of a destabilizing sigma effect relative to its D(3)(h) isomer. The molecule constitutes the largest substructure of archimedene hitherto synthesized.
authors.affiliation: Center for New Directions in Organic Synthesis, Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460, USA.
authors.forename: Dirk
authors.initials: D
authors.lastname: Bruns
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Miura
authors.forename: K Peter C
authors.initials: KP
authors.lastname: Vollhardt
authors.forename: Amnon
authors.initials: A
authors.lastname: Stanger