Synthesis of Aza-, Oxa-, and Thiaporphyrins and Related Compounds.

Chemical modification at the periphery with nitrogen or chalcogens is a highly promising strategy to diversify the optical, electrochemical, magnetic, and coordination properties of the porphyrin family. Indeed, various kinds of phthalocyanines and related benzo-annelated azaporphyrinoids have been synthesized, and their fundamental properties have been extensively investigated. However, the synthesis of heteroatom-containing porphyrins in which the peripheral methine groups are partially replaced with nitrogen or chalcogens remains a considerable challenge. In this review, we will focus mainly on recent advances in the synthesis of aza-, oxa-, and thiaorphyrins and related compounds, including historically important examples.