The synthesis is described of a porphyrin alcohol (22) which has a structure very similar to that of porphyrin a (2). The model porphyrin was resolved by separation of its camphanate esters. Ozonolysis of the 2-nitrobenzoate of each enantiomer in tritiated form gave a derivative of 2- hydroxypentanedioic acid whose configuration was determined by dilution analysis. It is demonstrated that correlation of the stereochemistry of porphyrin a with that of the model (22) will be possible by means of the 1H and 19F n.m.r. spectra of the corresponding esters with (-)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid.
Department of Chemistry
University of Cambridge