Pressure-dependent formation of bicyclo[3,2,0]hepta-1,4,6-triene, fulvenallene, and ethynylcyclopentadiene in the pyrolysis of 1,2-diethynylcyclopropane

Abstract

Thermolysis of trans-1,2-diethynylcyclopropane at pressures near 100 Torr produces only bicyclo[3,2,0]-hepta-1,4,6-triene; as the pressure is lowered, however, fulvenallene and ethynylcyclopentadiene became major components of the primary product distribution, indicating that the bicycloheptatriene is generated in a vibrationally excited form which, in time, can rearrange to the additional products observed at low pressure.