Direct meso-Alkynylation of Porphyrins Doubly Assisted by Pyridyl Coordination

Direct meso-alkynylation of beta,beta'-dlpyridylporphyrin with various alkynyllithium reagents has been achieved, in which the beta,beta'-dlpyridyl groups play an important role in facilitating the nucleophilic addition of the reagents through double coordination. This method enabled the synthesis of a meso-ethynylene-bridged diporphyrin.