title: Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes.
abstract: The photoisomerization of the pseudo-geminal tetraene 11 furnishes the cyclooctadiene derivatives 13 and 15 with a completely new type of molecular bridge for a [2.2]paracyclophane which promise many interesting novel applications; the same is true for the photoisomerization of 22 to 23 and 24. The structures of these new hydrocarbons were established by X-ray crystallography and spectroscopic analysis; among the noteworthy structural features of 13 and 15 are unusually long carbon-carbon single bonds (>1.64 Å).
authors.affiliation: Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany, / 391 5388.
authors.forename: Henning
authors.initials: H
authors.lastname: Hopf
authors.forename: Vitaly
authors.initials: V
authors.lastname: Raev
authors.forename: Peter G
authors.initials: PG
authors.lastname: Jones