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Title: The intramolecular trapping of acyllithium ions
Author: Hawes, A. C.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 1998
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There are few useful synthetic methods of treating organolithium with carbon monoxide to form acyllithium ions. Those which do exist involve in the main the use of extremely low temperatures. This is due to the extreme reactivity of those ions. In this project a reaction is developed using organolithium compounds in which an electrophile is incorporated. Upon formation of the acyllithium compound by exposing the organolithium compound to carbon monoxide electrophillic attack occurs on the incorporated electrophile to give a hetrocyclic product. Chapter 1 is a survey of the field of the reactions of acyllithium ions. In Chapter 2 the compounds investigated were N-tert-butoxycarbonylaniline, in the hope that the N-tert-butoxycarbonylaniline group would act as an ortho directing group and 2-bromo-N-tert-butoxycarbonylaniline which could be readily lithiated in the ortho position by means of a bromine-lithium exchange. The acyllithium compound formed from those compounds would not undergo intramolecular trapping however. In Chapter 3 N,N-dimethyl-N'-(2-bromophenyl)urea and its derivatives were used to form the corresponding dilithium compounds which were treated with carbon monoxide to give the acyllithium ions which underwent rapid intramolecular trapping to give isatins as the product in fair yield. In forming substituted starting materials the appropriate 2-bromo-4-substituted aniline was treated with triphosgene to convert this to the corresponding phenylisocyanate, which, in turn could be converted to the urea starting material. Those were, in turn used to form the substituted isatins. Chapter 4 describes the extension of this reaction to a hetrocyclic system. The compounds used were 2 and 4-(pivaloylamino)pyridine and substituted derivatives of 2-(pivaloylamino)pyridine. The lithiation reaction gave good yields on trapping with simple electrophiles but lower yields from the reaction in which the aza-dioxindole products were obtained.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available