Additions to porphins involving the formation of new carbon–carbon bonds
Abstract
Protoporphyrin IX dimethyl ester acts as a diene in Diels–Alder additions with dimethyl acetylenedicarboxylate and with tetracyanoethylene. The copper(II) complex of octaethylporphin reacts with ethyl diazoacetate to yield mainly two isomeric chlorins formed by carbene addition to the cross-conjugated double bonds on the porphin. A small amount of the meso-substituted porphin is also observed.