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Title: Copper- and nickel-catalysed N-arylation of cyanate salts
Author: Jepson, David
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2012
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The transition metal-catalysed N-arylation of cyanate salts represents an atom-economical approach to the synthesis of aryl isocyanates and isocyanate derivatives, which are commonly produced using hazardous reagents such as phosgene or azides. This thesis describes the development of copper and nickel-catalysed methodologies for the cross-coupling of aryl halides to commercially available cyanate salts, where reactions performed in the presence of various nucleophiles provide access to a wide range of useful products through intermolecular or intramolecular trapping. Firstly, an effective copper-catalysed system was developed using ligand screening and extensive optimisation work, allowing for the synthesis of aromatic carbamates, ureas and various heterocyclic compounds from aryl iodides. Though no isocyanates were isolated or detected during these experiments, this approach provided a novel, efficient method for the synthesis of these compounds. The 'reaction conditions were also used in the synthesis of commercial drug molecule Sorafenib, providing phosgene-free access to this valuable product. A nickel-catalysed variant was also developed, allowing for the synthesis of aromatic carbamates and ureas from inexpensive aryl bromides and chlorides, though issues of poor reproducibility meant that the reaction was of limited synthetic value. In the process of these investigations, a novel arylnickel(Il) cyanate complex was synthesised and its reactivity investigated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available