Reactivity of aqueous Fe(IV) in hydride and hydrogen atom transfer reactions

Oxidation of cyclobutanol by aqueous Fe(IV) generates cyclobutanone in similar to70% yield. In addition to this two-electron process, a smaller fraction of the reaction takes place by a one-electron process, believed to yield ring-opened products. A series of aliphatic alcohols, aldehydes, and ethers also react in parallel hydrogen atom and hydride transfer reactions, but acetone and acetonitrile react by hydrogen atom transfer only. Precise rate constants for each pathway for a number of substrates were obtained from a combination of detailed kinetics and product studies and kinetic simulations. Solvent kinetic isotope effect for the self-decay of Fe(IV), k(H2O)/k(D2O) = 2.8, is consistent with hydrogen atom abstraction from water.