Direct <i>meso</i>-Alkynylation of Porphyrins Doubly Assisted by Pyridyl Coordination

Direct meso-alkynylation of β,β′-dipyridylporphyrin with various alkynyllithium reagents has been achieved, in which the β,β′-dipyridyl 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.