An Efficient One-Flask Synthesis of N-Confused Tetraphenylporphyrin

<UFIGR ID="ol9910114n00001">N-Confused meso-substituted porphyrin is a porphyrin isomer previously available from one-flask porphyrin syntheses as a low-yield byproduct (&lt;7.5%). We have found that methanesulfonic acid catalyzed condensation of pyrrole and benzaldehyde followed by DDQ oxidation provides N-confused tetraphenylporphyrin (NC-TPP) in up to 39% yield in analytical scale experiments. Preparative synthesis provided an isolated yield of 35% (800 mg). This represents a >5-fold yield improvement and makes significant quantities of NC-TPP readily available.