Proposed mechanism for the selective oxidation of (1-OH) with CAN to verdoheme complex (4-X) via formation of intermediates (PIm+•)FeIV=O, isoporphyrin (2) and benzoyl-biliverdin (3). Drawings for analogs produced in the chemistry of (5-OH) are given in the Scheme S1. EPR and 2H-NMR data for complexes (1-OH; see SI), (5-OH; high-spin FeIII), (4-X; high-spin FeIII) generated in the crude reaction mixture (i.e., in situ), and for the isolated (4-X; high-spin FeIII), were also obtained (See SI).