Active metal template synthesis of rotaxanes, catenanes and knots

Abstract

The use of a chemical template to control the spatial arrangement of reactants revolutionized the synthesis of mechanically interlocked molecules. The recently developed ‘active metal template’ strategy, in which transition metal ions act as both the template to guide interlocking and as the catalyst for the covalent bond forming reaction that captures the interlocked structure, has several advantages in comparison with traditional ‘passive template’ approaches. In contrast with passive template approaches the active template strategy is more efficient, completing the assembly of the interlocked structure in one step instead of two and in some cases requiring only a substoichiometric amount of metal template. In addition, fewer permanent recognition sites are required and in certain cases the active template reaction can shed light on mechanistic details of related metalcatalyzed processes and act as a conduit for reaction discovery. This Thesis will discuss the expansion of this new methodology in two main directions: firstly, exploration of new active metal template reactions, specifically the application of a novel Ni catalyzed sp3–sp3 C–C bond forming reaction, and secondly, the application of previously developed active template reactions to the synthesis of agrochemical-based [2]rotaxanes and other architectures, macrobicyclic [3]rotaxanes, [2]catenanes and a trefoil knot.