Stereochemistry and steric isotope effect on the [2+2] photocycloaddition of β,β-dimethyl-p-methoxystyrene to C60: the nature of the transition state structures

The photochemical [2+2] cycloaddition of β,β-dimethyl-p-methoxystyrene to C60 occurs with loss of stereochemical integrity. The substantial remote kinetic isotope effect in the title reaction, indicates the formation of an open, relatively long lived intermediate.