Detailed mechanistic studies indicate that maximising pseudo-intramolecular "in-cage" radical-radical recombination is a requirement to generate the [1,2]-product with high enantiocontrol. Computational analysis supports the hypothesis of common [1,2]-and [2,3]-transition states and indicates that the [1,2]product is formed via preferential C-N bond homolysis of an ylide intermediate, followed by stereoselective recombination of an allylic radical with a catalyst-bound captodative radical.