Synthesis of a small molecule walker and the application of mechanically interlocked ligands in asymmetric catalysis

Abstract

This thesis reports the synthesis of a novel synthetic small molecule walker, a chiral [2]rotaxane and a single-handed trefoil knot. The last two were employed as ligands for metal catalysed asymmetric reactions.Chapter 1 explains what small molecule walkers are and their resemblance to nature's walking proteins. The motor protein myosin is discussed in more detail, followed by a section about small molecules that diffuse along a surface and recent advances in dynamic covalent walker systems.Chapter 2 shows the design and synthesis of a novel directional dynamic covalent walker. In the first section the concept is discussed. Afterwards, the synthesis of the walker and model system is described in detail.Chapter 3 is a short introduction about the history of interlocked molecules and the strategies that are applied to make them. The chapter highlights the formation of rotaxanes via the active metal template strategy. Also some useful features of rotaxanes are reviewed.Chapter 4 reports the use of a chiral macrocycle to construct a [2]rotaxane architecture via the Cu-catalysed Goldberg reaction. The threaded macrocycle also facilitates the Ni-catalysed asymmetric Michael addition of diethyl malonate and nitrostyrenes and gives improved enantioselectivity compared to a non-interlocked ligand.Chapter 5 is an extension on enantioselective catalysis with mechanically interlocked ligands. This chapter reports the first results of the application of a molecular trefoil knot in the lanthanide-catalysed Mukaiyama aldol addition.

Date of Award	1 Aug 2016
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Leigh (Supervisor)