2π + 2π]-Cycloaddition of biadamantylidene to 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione. Effects of temperature, high pressure, and solvent

Abstract

The effects of temperature, solvent nature, and high hydrostatic pressure on the rate of the reaction of biadamantylidene with 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione have been estimated. Significant shielding of the C=C double bond in biadamantylidene is responsible for the high entropy and volume of activation. Quantitative yield of the reaction in the temperature range 25‒45°C is related to its exothermicity. The rate of the [2π + 2π]-cycloaddition unexpectedly weakly depends on the solvent polarity, which makes it radically different from the [2π + 2π]-reaction with tetracyanoethylene.