Degenerate thermal isomerizations of bicyclo[3.1.1]hept-2-ene: Strategy and analysis

Bicyclo[3.1.1]hept-2-ene was first prepared and well identified in 1972. In 1974, the degenerate thermal isomerization involving 1-d- and 3-d-bicyclo[3.1.1]hept-2-ene was approached successfully, as one of the two deuterium-labeled structures was selected, heated, and equilibrated. There has been no further study of this degenerate isomerization. Here, a detailed outline of reaction trajectories for d₂-labeled bicyclo[3.1.1]hept-2-enes is given that will establish the four independent kinetic parameters needed for 20 linking paths between six d₂-species. The use of racemates, eliminating chiral separations and dissections, provides degenerate isomerization paths providing this method with general utility.