Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.732914
Title: Catalytic functionalisation of sp3 bonds
Author: Walton, Scarlett Maria
ISNI:       0000 0004 6494 860X
Awarding Body: University of Huddersfield
Current Institution: University of Huddersfield
Date of Award: 2017
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Abstract:
Reported herein is an investigation into palladium-catalysed -allylation employing sulfonamide nucleophiles. Anions of benzylsulfonamides have been shown to react with a series of allyl acetates in the presence of Pd0 catalysts, phosphine ligands and base at room temperature, enabling the synthesis of sp3-functionalised sulfonamides. The developed methodology has allowed access to a library of novel allylated sulfonamides, varying both amine substituent and allylic functionality. In addition, we have applied our methodology to a series of known sulfonamide drug targets, to demonstrate our reaction as a useful late-stage functionalisation tool, whilst populating chemical space. The performed mechanistic study using a stereospecific electrophile confirms benzylsulfonamides behave as soft carbon nucleophiles in the Tsuji-Trost reaction, as a ‘net retention’ of stereochemistry is observed (confirmed by X-ray crystallography). Moreover, the asymmetric synthesis of allylated sulfonamides is probed, although obtaining enantioselectivity a- to SO bonds is naturally difficult, due to the conformational preferences of sulfonamide carbanions. Traditional methods for direct -alkylation of sulfonamides require strong bases, reactive electrophiles, low temperatures and use of stoichiometric amounts of additives. Therefore, in addition to a catalytic method, we report an alternative method reacting benzylsulfonamides with allyl bromide electrophiles via a nucleophilic substitution reaction, using mild conditions (LDA, THF at –20 °C).
Supervisor: Sweeney, Joe ; Gill, Duncan Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.732914  DOI: Not available
Keywords: QD Chemistry
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