Gas-phase pyrolytic formation and dimerization of benzocyclobutenes: Synthesis of [2(4)](1,2,4,5) cyclophane.
Gas-phase pyrolysis of benzocyclobutenes in a nitrogen stream at 450 degrees C is a convenient efficient method for preparing dibenzocyclooctadienes. Application of this method to benzo[1,2;4,5]dicyclobutene gives [2(4)](1,2,4,5)cyclophane directly. However, under the same reaction conditions, 3,6-dimethylbenzo[1,2;4,5]dicyclobutene gives the open [2.2]orthocyclophane derivative, whose structure has been established by x-ray crystallographic analysis of the corresponding iron complex.
Eaton
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Department of Chemistry, University of Oregon, Eugene, Oregon 97403.
Laganis
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Boekelheide
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