Figure 3. Mechanistic studies of the catalytic enantioselective C(sp³)–C(sp³) cross-coupling.

a, Radical clock experiment with an alkene-tethered alkyl iodide 2n’ afforded the formation of 13 under standard conditions, suggesting the intermediacy of an alkyl radical and its subsequent cyclization and C(sp³)–C(sp³) coupling (see Supplementary Information section 12.4 for full details). b, Reaction was completely shut down by the addition of a radical scavanger TEMPO (see Supplementary Information section 12.5 for full details). c, Probe for origin of regioselectivity by using a tridentate Py-box ligand (L20) instead of L6 (see Supplementary Information section 12.6 for full details). d, Reactions with substrates where the alkenyl group is distal to the Bpin group: chain-walking products were formed with high enantioselectivity under standard conditions (see Supplementary Information section 13 for full details). e, Outline of a possible reaction pathway for Ni-catalysed enantioselective C(sp³)–C(sp³) cross coupling. r.r = Regioisomeric ratio; PMP = paramethoxyphenyl.