New methodology for the organocatalysed α-Amination reaction

 

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dc.contributor.advisor Hunter, Roger en_ZA
dc.contributor.author Msutu, Ath'enkosi en_ZA
dc.date.accessioned 2016-01-29T11:04:56Z
dc.date.available 2016-01-29T11:04:56Z
dc.date.issued 2015 en_ZA
dc.identifier.citation Msutu, A. 2015. New methodology for the organocatalysed α-Amination reaction. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/16608
dc.description Includes bibliographical references en_ZA
dc.description.abstract Research into organocatalyzed asymmetric reactions has been a rapidly growing and competitive field in recent times, wherein amino catalysis is widely used for the asymmetric functionalisation of carbonyl compounds. Since its simultaneous publication by List and Jørgensen, the organocatalysed α-amination reaction has become a key method for asymmetric heteroatom functionalisation of carbonyl compounds. Herein we report the first application of this methodology to acetals, with the ultimate goal of applying the methodology to the asymmetric desymmetrisation of bis-acetals as a novel contribution to this growing field. Following extensive optimisation, acidic reaction conditions for the reaction were established in which dibenzyl azodicarboxylate (DBAD) was used as the aminating agent and (S)-(-)-5-(2-pyrrolidinyl)-1H-tetrazole as the preferred organocatalyst. The desired aminated products were obtained in high yields and enantioselectivities. The reaction showed broad substrates cope in its application to ketals, dioxolanes and lactols. A hydrazide N-N bond cleavage methodology was also developed for the aminated products in oxazolidinone form. This methodology is based on Magnus' alkylation / E1CB strategy. The novel contribution here is using ditheyl bromoacetate as an alkylating agent and as a better elimination partner. A range of bis-acetals were synthesised via three synthetic routes using malonate-, sulfone and cyclopentene-based synthesis strategies. The acetal reaction was used for the desymmetrisation of two of these bisacetals as a proof of concept. This is a feat not achieved with the more reactive dicarbonyl analogue. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Chemistry en_ZA
dc.title New methodology for the organocatalysed α-Amination reaction en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Chemistry en_ZA
dc.type.qualificationlevel Doctoral en_ZA
dc.type.qualificationname PhD en_ZA
uct.type.filetype Text
uct.type.filetype Image


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