Mechanically interlocked architectures via active-metal template strategies
In contrast to the classic ‘passive template’ approach, an ‘active-metal’ template strategy involves a metal centre which acts as both a template and the catalyst for covalent bond formation in the construction of mechanically interlocked architectures. The crucial formation of a covalent bond between two ‘half-threads’ is promoted by the catalyst and directed through the cavity of the macrocycle by the catalyst’s coordination requirements. The main attractive features of such a synthetic approach are the efficiency (as one step is required instead of two), the rapid assembly of inaccessible structures, the possibility of ‘traceless’ assemblies, the versatility, the possibility to use catalytic amount of the metal template and to provide mechanistic insight. This novel concept was successfully introduced by our group and applied to a wide range of well-known transition metal-catalysed reactions. The thesis will present several examples of active-metal template reactions for the synthesis of interlocked architectures, including Cu(I)-catalysed alkyne-azide cycloaddition (CuAAC popularised as the click reaction), Pd(II)-catalysed alkyne homocouplings Pd(II)-catalysed oxidative Heck cross-couplings and Lewis acids mediated Diels-Alder reactions.