One significant study involved the photocycloaddition of fullerene 1 to the three geometric isomers of 2,4-hexadiene (2) (Figure ) . From the product 4 distributions with the various isomers of the diene 2, the authors calculated for the proposed intermediate 3 a ratio of the rate of rotation about the bond that was originally a double bond in the diene 2 and the rate of ring closure of the intermediate 3. The present study reinterprets the reported data to give rate ratios that are different from the one reported. . .