Reactivities of amino acid derivatives toward hydrogen abstraction by Cl⚫ and OH⚫

In recent computational studies of hydrogen-atom abstraction from amino acid derivatives, two distinct rationalizations have been put forward for the relative inertness of the α-C–H. Of these, the proposal that the inertness is due to a “kinetic trap” associated with particularly stable complexes is shown to be unlikely because of unfavorable entropies. On the other hand, the proposed existence of deactivating polar effects at the α-position in Cl^• abstractions is likely also to be applicable to OH^• abstractions, but to a lesser extent.