ALKYLATION OF THE alpha AND gamma MESO POSITIONS OF TETRAPHENYLPORPHYRIN UPON REDUCTION OF ALLYL AND PROPARGYL BROMIDE BY IRON(II) TETRAPHENYLPORPHYRIN: A NEW ROUTE TO PORPHODIMETHENE COMPLEXES.

Article abstract of DOI:10.1021/ja00330a030

Reduction of allyl bromide by sodium ascorbate or sodium dithionite, under anaerobic conditions, is catalyzed by (5,10,15,20-tetraphenylporphinato)iron(II). 1,5-Hexadiene has been found to be the only organic product. During this reaction, the iron porphyrin complex is slowly transformed into a mixture of stereoisomers of the (5,15-diallyl-5,10,15,20-tetraphenylprophinato)iron(II) complex. These new complexes, which were found to be very sensitive to dioxygen, have been demetalated into the corresponding stable diallyporphodimethenes whose structure has been established by elemental analysis and spectroscopic techniques. In the case of propargyl bromide, a similar alkylation of the meso positions of the iron porphyrin occurs, by either an allenyl or a propargyl group, leading to stereoisomers of the (diallenyl-, (dipropargyl-, and (allenylpropargylporphodimethene)iron(II) complexes.