Kinetics and thermochemistry of the [2π+2σ+2σ]-cycloaddition of quadricyclane with 2,3-dicyano-1,4-benzoquinone

Abstract

© 2019 Wiley Periodicals, Inc. Two-stage [2π+2σ+2σ]-cycloaddition of quadricyclane (2) with 2,3-dicyano-1,4-benzoquinone (1) with a huge difference in the activity of two reaction centers has been studied. In the first stage (kinetic control), the cycloaddition of 2 takes place on the activated С 2 =С 3 bond of 1 to form the monoadduct 3, and in the second stage the cycloaddition of 2 on the С 5 =С 6 bond of the monoadduct 3 occurs by 6 orders of magnitude lower with the formation of bisadduct 4. The structures of adducts 3 and 4 have been proved by NMR data and the X-Ray method, respectively. The kinetics of the first and second stages, the enthalpy of dissolution of 1 in the π-donor solvents, and the enthalpy of the reaction 1+2→3 have been measured.