Chapter 6 - Michael addition reaction in electroorganic synthesis

Abstract

The use of electrochemical methodology has many potential advantages over traditional organic syntheses. The majority of organic electrode reactions is characterized by the generation of a reactive intermediate at the electrode by electron transfer (ET) and subsequent reactions typical for that species. Thus the oxidation or reduction step initiates the follow-up chemistry to the reaction products (“doing chemistry with electrodes”). Species with electron deficiency (e.g., carbocations), unpaired electrons (e.g., radicals, radical ions), electron excess (e.g., carbanions), or those with unusual oxidation states (e.g., metal complexes with low- or high-valent central atoms) are produced at the electrode. Electrochemical generation of such intermediates may be advantageous because of the mild reaction conditions employed (room temperature, strong acids or bases are not necessary) and/or the additional selectivity introduced in controlled-potential experiments. The reaction mechanisms of organic electrode reactions are thus composed of at least one ET step at the electrode as well as preceding and follow-up bond-breaking, bond-forming, or structural rearrangement steps. These chemical steps may be concerned with the ET. Michael addition reactions have been discussed as a chemical step, here The versatility of the Michael reaction in terms of monomer selection, solvent environment, and reaction temperature permits the synthesis of sophisticated macromolecular structures under conditions where other reaction processes will not operate. The utility of the Michael addition in many biological applications such as gene delivery, polymer drug conjugates, and tissue scaffolds is discussed in relation to macromolecular structure. In this chapter, we try to review the practical aspects in the ET reactions that are coupled with Michael addition reaction with the hope of encouraging synthetic organic chemists to contemplate it, as an efficient and green strategy when it is required in their designed multistep reaction pathways.