Homogenous redox catalysis competition between electron exchange and proton exchange

Mechanistic investigation of the iron-mediated electrochemical formation of β-hydroxyesters from α-haloesters and carbonyl compounds

“…This demonstrates an indirect reduction of methyl 2-chloropropanoate carried out via homogeneous redox catalysis. This is also supported by results reported by Inesi and Zeuli dealing with the reduction of b, c, and d-bromoesters in the presence of various redox mediators [26][27][28]. Moreover, when electrogenerated Fe I (see the above part) was treated with 1 molar equivalent of methyl 2-chloropropanoate under argon, iron(II) was regenerated and detected by in situ cyclic voltammetry.…”

“…It must be pointed out that methyl 2-bromopropanoate is reducible at À1.8 V under the same conditions (electrode, scan rate, etc.). On the basis of our results and of those reported by Zeuli and Inesi dealing with the indirect and direct reduction of bromoesters, the reduction of a-haloesters therefore leads to the corresponding radical-anion along with the regeneration of Fe II [26][27][28][29][30]. The radical-anion then undergoes a cleavage affording an ester radical and a free halide ion.…”