CHAPTER ONE reviews the literature, discussing aspects of transition metal mediated
asymmetric catalysis in the presence of enantiomerically pure ligands.
CHAPTER TWO discusses the asymmetric addition of dialkyl-zinc reagents to aromatic
aldehydes. The work presented is particularly concerned with the design and
construction of enantiomerically pure oxazoline ligands tethered to alcohols These
ligands have proved effective in the acceleration of the alkylation reaction and are able
to influence good levels of asymmetric induction in the resultant secondary alcohol
CHAPTER THREE examines the electronic (and steric) effects of enantiomerically pure
oxazoline ligands for the palladium catalysed allylic substitution reaction. Using
ligands possessing two electronically different donor atoms, it is possible to create
electronic distortion upon the intermediate allyl complex. In doing so it is possible to
direct nucleophilic addition to one carbon centre preferentially to the other, resulting in
asymmetric induction. Manipulation of these ligands enables control in the extent of
electron distortion inflicted upon the allyl complex and consequently influences the
levels of enantioselectivity observed.
CHAPTER FOUR investigates the ability of hydrolytic enzymes to kinetically resolve a
series of allylic acetates, under varying conditions. Lipases appeared superior to
esterases for the substrates employed. In particular cis-3-acetoxy-5-carbomethoxycyclohexene was smoothly resolved m high yield and enantioselectivity.
CHAPTER FIVE reports on the potentiality of a dynamic resolution of allylic acetates, using
hydrolytic enzymes in the presence of a palladium catalyst. A proposed mechanism is
discussed. Initial results are promising, however, the sensitivity of the reaction is
realised and optimisation of conditions still needs to be addressed.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.