To investigate the effects of electron-donating and electron-withdrawing substituents upon the reaction of porphyrins with osmium tetraoxide, and the pinacol-pinacolone rearrangement of the resulting diols, a series of meso-substituted porphyrins were prepared by total synthesis. Porphyrins with electron-donating substitutents at the meso-positions gave vic-dihydroxychlorins in which the adjacent pyrrole subunit was predominantly ...
[Robinson, John A.; McDonald, Edward; Battersby, Alan R. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1985 , p. 1699 - 1710]