Thesis

A quantitative scale for directing group power in ruthenium(II)-catalysed ortho-directed C-H arylation reactions

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2017
Thesis identifier
  • T14744
Person Identifier (Local)
  • 201483434
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Directed ruthenium-catalysed C-H functionalisation of heteroarenes, such as 2-phenylpyridineor 1-phenylpyrazole, has emerged as an efficient and environmentally benign alternative totraditional cross-coupling chemistry. Using readily available and inexpensive aryl halides, themechanisms of these transformations are beginning to be understood. However, there has beenno work completed towards understanding the different directing group power of thesesubstrates. Many of the literature examples consider only the behaviour of substrates with onefunctional group, and the behaviour of more densely functionalised substrates remainsunpredictable.In this work we have presented a quantitative reactivity scale of directing group power for aseries of ruthenium(II)-catalysed ortho-directed intermolecular C-H arylation reactions acrossa range of substrates. The scale of directing group power has been determined using sets ofcompetition reactions that were analysed by calibrated GC-FID. Using least squaresminimisation, relative reaction rates were obtained for each substrate delivering the firstquantifiable assessment of directing group power.These results have found that, in our series, 2-phenylpyridine >> 2-phenylpyrazole > Nmethyl-2-phenyl-imidazole > 2-phenyloxazoline >> N-(1-phenylethylidene)aniline. Theseresults cover a synthetically useful reactivity range of 10²and allow a quantitative predictionof site selectivity under the conditions examined.Additionally, we have presented initial experimental findings that support the intermolecularquantitative predictions within an intramolecular substrate. This sets the scene for predictionof regioselectivity in more densely functionalised molecules, on an inter- and intramolecularsetting.
Advisor / supervisor
  • Nelson, David
Resource Type
Note
  • Previously held under moratorium from 19 October 2017 until 24 February 2022
DOI
Date Created
  • 2017
Former identifier
  • 9912569292502996
Related items
Embargo Note
  • This thesis is restricted to Strathclyde users only until 19 October 2022

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