Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505382
Title: Stereocontrol in rotationally restricted ureas
Author: Turner, Hazel L.
Awarding Body: The University of Manchester
Current Institution: University of Manchester
Date of Award: 2008
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Abstract:
Atropisomerism is a property exhibited by molecules where rotation about one or more bonds is restricted. Along with the biaryls, which are widely utilised in asymmetric catalysis most famously by BINAP and BINOL, several other classes of compounds display atropisomerism, primarily aiiilides, benzamides and biaryl ethers. These molecules have applications in enantioselective synthesis, asymmetric catalysis and been used to relay stereochemical information (Chapter 1). This thesis presents a new family of non-biaryl type atropisomers; rotationally restricted diarylureas. Chapter 2 explains how these aromatic ureas can be ring selectively functionalised using regioselective N-alkylation and directed ortho metalation. The chapter also describes how we have used these methodologies to synthesise some diastereomeric atropisomers. Chapter 3 reports the lateral lithiation of some diarylureas to yield diastereomeric atropisomers stereoselectively. We go on to show that, in these reactions, the sense of the diastereoselectivity is electrophile dependent. Several reaction pathways exist in lithium substitution sequences and Chapter 4 describes these routes and our attempts to use (-)-sparteine in laterallithiation reactions to determine the configurationally integrity of our organolithium. s . Finally, our efforts to synthesise some enantioenriched atropisomers from the diarylurea family using chiral sulfoxides is described in Chapter 5. This chapter also describes how an enantioenriched atropisomer is obtained using a kinetic resolution.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.505382  DOI: Not available
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