Conformationally constrained thyroliberin analogs: a novel electrochemical route to a key rigid Pro-Phe building block

An anodic amide oxidation has been employed in the synthesis of a rigid Pro-Phe building block. The key electrochemical step allowed for the functionalization of a proline derivative and led to an annulation procedure for conveniently constructing the bicyclic ring system used to lock the dipeptide building block into a specific conformation.