有機電解合成のための機能性界面の構築

抄録

  Thin poly (acrylic acid) (PAA)-coated graphite felt (GF) is a promising electrode material for preparative organic electrosynthesis, because the electrode is not only stable and durable but also can be modified with various mediators and enzymes in the PAA layer. The TEMPO-modified GF electrode for electrocatalytic oxidation of several types of organic compounds were successfully constructed. The modified electrode had many advantageous properties compared with direct electrosynthesis or mediatory reaction synthesis which is still common as an electrochemical system. The use of a chiral nitroxyl radical-modified GF electrode afforded enantioselective oxidation of racemic alcohols or amines (remaining optically pure alcohols or amines) and asymmetric lactonization of methyl-substituted diols. A preparative electrocatalytic radical cyclization of bromo alkyl cyclohexenones was successfully achieved on a nickel (II) tetraazamacrocyclic complex-modified GF electrode. The PAA-coated GF electrode modified with viologen and palladium metal microparticles is effective for the electrocatalytic hydrogenation of olefins. An electrode immobilizing all components of mediator, enzyme, and coenzyme for electroenzymatic reactions was also prepared, and several electroenzymatic reactions were smoothly carried out. Substrate immobilization on GF for the solid-phase acetylene coupling reaction was achieved by electrochemical polymerization of the substrate precursor containing a pyrrole side chain, where the amount of substrate on the electrode surface was easily controlled by the number of repeated cyclic voltammetric scanning. Couplings between terminal acetylenes and the iodobenzene-modified GF electrode or aromatic iodides and the terminal acetylene-modified GF electrode in the presence of palladium catalyst proceeded smoothly with satisfactory yields.