Reductive Benzylation of C-70 Imidazoline with a Bulky Addend

Abstract

Reductive benzylation of C-70 imidazolines bearing a bulky addend has been carried out under conditions similar to that reported for C-60 analogues. However, different from the reaction of C-60 analogues, the reaction of C-70 imidazolines not only results in adducts with 1,2,3,16-configuration due to the steric effect, but also a considerable amount of dibenzylated and monobenzylated products with 1,2,3,4-configuration, demonstrating a reactivity difference between C-60 and C-70. Interestingly, the anions of the 1,2,3,16-C-70 adduct are rather stable as shown by the electrochemical study, which is in contrast to the anions of 1,2,3,16-C-60 counterparts, and can be rationalized by the electronic structure difference between C-70 and C-60 derivatives