The identity of inner-sphere radical capture transition states TS1a and TS1b are supported by experimental observations. Yields and e.r. are increased when employing electron-withdrawing substituents on the heteroaryl coupling partner (Table ). This observation can be rationalized by the substituents removing electron density from the critical Ni-bound carbon, thereby aiding the inner-sphere radical capture. Furthermore, radical clock competition kinetics experiments were performed using a 5-hexenyl sulfonylhydrazide (Figure ) as precursor to a 5-hexenyl primary radical. It was hypothesized that a free radical pathway (such as that proposed in our previous report for entry into a racemic Ni(I)/Ni(III) cycle) would preferentially encounter the cyclized radical after irreversible 5-exo-trig ring closure when compared to the present reaction conditions;