Albert Padwa,* William F. Rieker, and Robert J. Rosenthal ... Department of Chemistry, Emory University, Atlanta, Georgia 30322 Received October 19, 1983 ... The thermal and photosensitized reactions of several 4-(methyldiphenylcyclopropenyl)-l-butenes have been studied. The thermolysis of these systems gave substituted tricycle[ 3.2.0.@+']heptanes in good yield. The formation of this ring system involves bond formation between the ir-bond and the cyclopropene ring ...