Unfortunately, applying the optimized conditions to primary and secondary amines resulted in undesired polar reactivity. Here, the less sterically hindered amines would undergo nucleophilic addition to the imine and our focus turned to substrates in which the nitrogen was protected by the tert-butyloxycarbonyl (Boc) protecting group. To evaluate this approach, Boc-pyrrolidine 4a was selected as the model substrate. Since the lone pair of the nitrogen is deactivated, the oxidation potential of these deactivated amine substrates is higher than that of their unprotected analogs. We surmised that a HAT pathway seemed most feasible. Both iHAT and direct hydrogen atom transfer (dHAT) systems were examined, and tetra-n-butylammonium decatungstate (TBADT) was ultimately identified as the dHAT catalyst, delivering product 5a in 76% yield.