Facile meso Functionalization of Porphyrins by Nucleophilic Substitution with Organolithium Reagents

The ruffle of the porphyrin increases with the number of meso substituents. (Octaethylporphyrin)nickel(II ) undergoes nucleophilic substitution reactions upon treatment with alkylating reagents such as butyllithium, hydrolysis with water, and oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone DDQ; Eq. (a)]. Alkylation can be achieved at all four meso positions, and access is provided to new nonplanar porphyrins and asymmetrically substituted systems.