Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490122
Title: The synthesis of novel water-soluble azacalixarenes and the synthesis of atropisomers : controlling axial chirality
Author: Rowbottom, Stephen John Mark
ISNI:       0000 0001 3538 5308
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2008
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Abstract:
A highly convergent and efficient fragment coupling strategy was implemented to assemble a variety of readily available triazine, amine and diamine molecular building blocks, to prepare an array of novel, highly functionalised water-soluble azacalixarenes. These unique compounds adopt a 1,3-alternate conformation in their energetic ground state and possess a 'pocket' within the cavity, which has the potential to bind small guest species inside. The synthesis, structure and binding properties of these unprecedented compounds are described herein. H I H-N R The Synthesis ofAtropisomers; Controlling Axial Chirality A general method applicable for the asymmetric synthesis of biaryl compounds, containing a pyridine or isoquinoline group, as a key structural feature was investigated. The strategy implemented involved the use of an enantiomerically pure chiral sulfoxide auxiliary which, when introduced ortho to a kinetically constrained biaryl axis was found to impart a high level of stereochemical control, through complementary electronic and steric effects. The introduction of the sulfoxide auxiliary resulted in the formation of two diastereomers and permitted a dynamic thermodynamic resolution; this generated the thermodynamically more stable atropisomer in an overall yield greater than 50%. A suitable method to remove the sulfoxide stereocentre whilst ensuring the transfer of enantiopurity in the final products was then explored. Oxidation of the sulfoxide group removed the stereocentre and gave a sulfone as the product with complete retention of enantiopurity (99: 1 er). A sulfoxide-lithiumelectrophile exchange reaction using phenylithium enabled the asymmetric synthesis of QUINAP, implementing a dynamic thermodynamic resolution into the strategy gave an overall yield of 58%. Finally, a number of racemic ortho substituted aryl pyridines were prepared to assess the effect of substituent size on the barrier to rotation, the barriers were quantified using variable temperature NMR.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.490122  DOI: Not available
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