%0 Journal Article
%A Hamed, Emad M.
%A Doai, Hanh
%A McLaughlin, Christopher K.
%A Houmam, Abdelaziz
%D 2006
%T Regioselective Bond Cleavage in the Dissociative Electron
Transfer to Benzyl Thiocyanates: The Role of Radical/Ion Pair
Formation
%U https://acs.figshare.com/articles/journal_contribution/Regioselective_Bond_Cleavage_in_the_Dissociative_Electron_Transfer_to_Benzyl_Thiocyanates_The_Role_of_Radical_Ion_Pair_Formation/3221110
%R 10.1021/ja056730u.s001
%2 https://ndownloader.figshare.com/files/5055037
%K Dissociative Electron Transfer
%K regioselective bond cleavage
%K substituent
%K anion
%K dissociative electron transfer theory
%K formation
%K ET
%K extension
%K reductive cleavage mechanism
%K CH 3 O
%K thiocyanate
%K regioselective reductive bond cleavage
%K benzyl
%K Regioselective Bond Cleavage
%K electrochemical reduction
%X Important aspects of the electrochemical reduction of a series of substituted benzyl thiocyanates
were investigated. A striking change in the reductive cleavage mechanism as a function of the substituent
on the aryl ring of the benzyl thiocyanate was observed, and more importantly, a regioselective bond
cleavage was encountered. A reductive α-cleavage (CH2−S bond) was seen for cyano and nitro-substituted
benzyl thiocyanates leading to the formation of the corresponding nitro-substituted dibenzyls. With other
substituents (CH3O, CH3, H, Cl, and F), both the α (CH2−S) and the β (S−CN) bonds could be cleaved as
a result of an electrochemical reduction leading to the formation of the corresponding substituted
monosulfides, disulfides, and toluenes. These final products are generated through either a protonation or
a nucleophilic reaction of the two-electron reduction-produced anion on the parent molecule. The dissociative
electron transfer theory and its extension to the formation/dissociation of radical anions, as well as its
extension to the case of strong in-cage interactions between the produced fragments (“sticky” dissociative
electron transfer (ET)), along with the theoretical calculation results helped rationalize (i) the observed
change in the ET mechanism, (ii) the dissociation of the radical anion intermediates formed during the
electrochemical reduction of the nitro-substituted benzyl thiocyanates, and more importantly (iii) the
regioselective reductive bond cleavage.
%I ACS Publications