Kinetic, thermodynamic and mechanistic studies on the reduction of carbenium ions by NAD(P)H analogues

Abstract

Hydride transfer mechanisms of the reductions of xanthylium ion by NAD(P)H analogues (i.e. BNAH, HEH and AcrH2) were investigated. Both the kinetic observations and an analysis of thermodynamic driving forces for each mechanistic step in all the possible mechanisms indicate that the reductions are initiated by a rate‐determining electron transfer, followed by a fast hydrogen atom abstraction. The mechanism of the reductions of 9‐phenylxanthylium and triphenylmethylium ions by BNAH were also investigated and are similarly discussed. © 1997 John Wiley & Sons, Ltd.

Heterolytic and Homolytic N−H Bond Dissociation Energies of 4-Substituted Hantzsch 2,6-Dimethyl-1,4-dihydropyridines and the Effect of One-Electron Transfer on the N−H Bond Activation

“…Well-behaved irreversible peak potentials ( E p ) were recorded. Similar phenomena were commonly observed in the literature (e.g., refs , , , , and 14) where the uncertainties caused by electrode irreversibility were believed to <2 kcal for absolute values and much smaller for relative values.…”

Electron paramagnetic resonance spectroscopic studies of the electron transfer reaction of Hantzsch ester and a pyrylium salt

“…The individual EPR spectra of the different DMPO-adducts are presented in Fig. 3 together with our proposed structures (also supported by literature data 3 ) corresponding to each spectrum. Table 1 summarizes the fitted hyperfine splitting constants for the five detected components.…”

Energetics of Multistep versus One-step Hydride Transfer Reactions of Reduced Nicotinamide Adenine Dinucleotide (NADH) Models with Organic Cations and p-Quinones

“…Therefore, the situation for the Group I reductions are expected to be similar (i.e., via electron transfer). In fact, the very low e - T barriers found for this group of reactions suggest that this should be the case.…”