THERMOLYSIS OF CIS-1,2-DIDEUTERIOCYLOBUTANE AND TRANS-1,2-DIDEUTERIOCYCLOBUTANE

The synthesis and stereochemistry of thermolysis of cis- and trans-1, 2-dideuteriocyclobutane is reported and the results are compared to previously calculated models of tetramethylene. Cis-trans isomerization of dideuterio cyclobutane and complete cis-trans isomerization of ethylene-d2 were observed. The fragmentation/isomerization ratio of 3.0 obtained at low fractional isomerization is consistent with a potential energy surface for tetramethylene, which is symmetric with regards to fragmentation and recombination. The rapid methylene rotation necessary to explain the observed stereochemical features of the reaction also limits the magnitude of the “through-bond coupling” interaction to a value comparable to the magnitude of the potential energy well. © 1979, American Chemical Society. All rights reserved.