Ligand-assisted nickel-catalysed sp3-sp3 homocoupling of unactivated alkyl bromides and its application to the active template synthesis of rotaxanes

An efficient, mild and operationally simple Ni-catalysed sp(3)-carbon-to-sp(3)-carbon homocoupling of unactivated alkyl bromides has been developed and utilised in the active metal template synthesis of an alkyl chain axle [2]rotaxane. The key to the transformation is the use of tridentate nitrogen-donor-atom (terpy or pybox derived) ligands which inhibit competing beta-hydride elimination of alkyl-Ni intermediates.