Carbenic philicity and the ‘intrinsic reactivity index’

The reactivity of electrophilic, ambiphilic, and nucleophilic singlet carbenes is considered in terms of a recently proposed ‘intrinsic reactivity index’ (IRI). Comparisons of IRI are made with previously described analyses, and it is concluded that IRI is not as useful for the determination or analysis of carbene philicity as FMO-based or empirical treatments.