ChemInform Abstract: Acid-Catalyzed Electron-Transfer Processes in Reduction of α-Haloketones by an NADH Model Compound and Ferrocene Derivatives.

ChemInform Abstract

The NADH model compound (II) shows no reactivity toward araliphatic α-haloketones such as (I) in MeCN at 335 K in the dark. When HClO₄ is added to the (I)/(II) system, however, the haloketone is readily reduced to yield the parent ketone, e.g. (III), the corresponding halohydrin (IV), and the 10-methylacridinium ion. Product ratios (III)/(IV) vary depending on (I); kH/kD is found to be 3.0, 2.7, and 1.9 for R: -H, -Me, -O-Me, resp., and 5.0 for the reduction of Ph-CO-CH2-Cl. Despite the fact that reduction of Ph-CO-CH2-Cl and of (I) (R: -H, -O-Me) by 1,1'-dimethylferrocene and analogs only leads to the ketone (III) (R: -H, -O-Me; yield 100%), linear correlations between the kinetics of both reductions indicate a common activation process, i.e. acid-catalyzed single electron-transfer from (II) to protonated (I).