High-Pressure Addition Reactions Involving Cycloheptatriene-Norcaradiene Equilibrium

Article abstract of DOI:10.1021/jo00355a002

Several high-pressure reactions of cycloheptatriene (CHT) were investigated with various unsaturated compounds.With homonuclear bonds (C=C,CC, N=N),norcaradiene adducts were formed, whereas with the unsymmetrical C=O bond, only ene-type addition was observed.There is a general tendency to form norcaradiene adducts under high pressure (reactions of CHT with acrylonitrile and acetylenic bonds).Several unprecedented peculiar features are observed under pressure: inter- and intramolecular formation of the norcaradiene adduct (CHT-dimethyl acetylenedicarboxylate),homo Diels-Alder reactions involving bicyclooctadiene systems (CHT-methylpropiolate), formation of the unknown norcaradiene adduct with the N-N fragment (CHT-diethyl azodicarboxylate) showing interesting NMR properties reflecting conformational changes.