Elucidation of complex reaction mechanisms through the application of density functional theory

  • Krystian Kolodziejczak

Student thesis: Doctoral Thesis

Abstract

The combination of triethylsilane and potassium tert–butoxide is known as the Grubbs–Stoltz reagent pair, named after the chemists who first described its reactivity. The reagent pair has been suggested to form three reactive intermediates A–C in situ: [graphic element here] Exposure of a substrate to these three reactive species simultaneously allows for interesting complex mechanistic scenarios due to the wide range of chemistry provided: radical, single electron transfer, and anionic. This thesis reports the outcome of studies that have used density functional theory to explore the mechanism of three different reactions mediated by the triethylsilane/potassium tert–butoxide system. Examples of substrates undergoing the transformations studied are shown below as D, H and J. In each case, the calculations provided rational solutions for the unusual reaction types. [graphic element here] Additionally, amination reactions such as the conversion of M to O were studied using density functional theory. The reaction is known to afford aminated arene products under (i) transition metal and (ii) transition metal–free conditions. Calculations into the mechanism provide a plausible mechanistic proposal for both sets of conditions. Both pathways are initiated by protonation of M by triflic acid, after which they diverge into their own mechanistic routes before converging upon formation of an electrophilic piperidine radical cation via N–O bond cleavage. A propagation cycle is proposed to feature in the mechanism under both sets of conditions. [graphic element here]
Date of Award9 Mar 2023
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorJohn Murphy (Supervisor) & Tell Tuttle (Supervisor)

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