Ruthenium‐Catalyzed Oxidation of the Porphyrin β,β′‐Pyrrolic Ring: A General and Efficient Approach to Porpholactones

We describe an efficient ruthenium‐catalyzed oxidation of the β,β′‐pyrrolic ring on the porphyrin periphery. Through the conversion of a β,β′‐double bond to a lactone moiety, the direct preparation of porpholactones from porphyrins is achieved, which previously suffered from needing toxic reagents, multiple synthetic steps and low yields. The generality of this method has been investigated with various porphyrins with different electronic and steric effects, even some metalloporphyrins, and so represents a general and efficient approach for the synthesis of the intriguing porpholactone derivatives.