Restriction lift date: 2023-05-30
Telescoping of transition metal catalysed and biocatalysed reactions
University College Cork
This thesis describes the telescoping reactions which exploit the diverse catalytic approaches of transition metal catalysis and biocatalysed processes. These processes would normally have conditions that are incompatible. Telescoping these processes into a single process will provide powerful enantioselectivity which exploits the efficiency of transition metal catalysis and the stereoselectivity of biocatalysis. Chapter one provides an overview of asymmetric synthesis, both –diazocarbonyl compound synthesis and reactions, and biotransformations. It also gives an overview of telescoping systems from the literature. The results of this research are discussed in both chapter two and three. Chapter two describes the initial work undertaken during this project including attempting intramolecular X–H insertion reactions and intramolecular C–H insertion and then the Baker’s yeast reduction of those products. The batchwise step–by–step transformations were undertaken initially and then telescoped together overcoming problems associated with the process. Chapter three describes the C–H intramolecular reactions with both rhodium (II) acetate and copper (II) triflate to produce a range of 2–benzenesulfonyl substituted cyclopentanone compounds. These compounds were then kinetically resolved via a Baker’s yeast mediated reduction. These individual steps were optimised before they were telescoped together. The range of 2–benzenesulfonyl substituted cyclopentanone compounds also underwent ring cleavage to give simple carboxylic acids which could then be desulfonylated to simple alcohol compounds with a stereocentre in the middle of the chain. Chapter four contains the full experimental details and spectral characterisation of all the compounds synthesised in this project, while the details of the chiral stationary phase HPLC analysis is included in the appendix.
Chemistry , Biocatalysis , Reaction telescoping , Organic chemistry , Synthetic chemistry , Transition metal catalysis
Kelly, A. C. 2020. Telescoping of transition metal catalysed and biocatalysed reactions. PhD Thesis, University College Cork.