Unexpected one-pot synthesis of A3-type unsymmetrical porphyrin

The first direct synthesis of A3-type unsymmetrical porphyrin is achieved via conventional pyrrole-aldehyde condensation in a one-pot procedure in an appreciable yield. Generalization of this approach to a variety of other aldehydes revealed that it is advantageous for highly electron-rich aldehydes giving unsymmetrical porphyrin, while electron-poor aldehydes even failed to cyclize under the same experimental conditions.