Evidence for a Fast (Major) and Slow (Minor) Pathway in the Schumm Devinylation Reaction of Vinyl Porphyrins

Article abstract of DOI:10.1021/jo00330a023

The devinylation of protohemin in molten resorcinol is shown to proceed by two pathways.Two of the three possible intermediates in the minor (slow) pathway have been isolated and characterized as their dimethyl esters.In both, C-alkylation of resorcinol at the porphyrin C-1' vinyl side chains has occured.These intermediates are, however, converted into deuterohemin far too slowly for them to be on the major pathway from protohemin to deuterohemin.It is suggested that other intermediates, possibly in which O-alkylation of resorcinol has occurred, are intermediates in the major (fast) pathway from protohemin to deuterohemin.