UBC Theses and Dissertations
Leveraging automation to elucidate reaction mechanisms Malig, Thomas
Understanding chemical processes facilitates reaction optimization to make synthetic procedures more efficient while also enabling reaction discovery. Temporal profiling of chemical reactions provides the gold standard for increasing mechanistic understanding. Unfortunately, obtaining time-course information reproducibly, accurately, and also minimizing analyst intervention is a significant challenge. Combining in situ spectroscopic methods with automated sampling techniques provides a robust method to generate kinetic profiles enabling increased mechanistic understanding. This thesis explores the development and application of online HPLC as an analytical technique to obtain concentration data while minimizing workload for the analyst. By utilizing commercially available laboratory equipment and software we have created a sampling device capable of automatically monitoring both homogeneous and heterogeneous reactions, as well as those performed under an inert atmosphere. The ability of the platform to sample, dilute, mix, and analyze reaction aliquots reproducibly has been validated, thereby ensuring accuracy of acquired time-course data. This automated reaction monitoring device has been used to delineate reaction mechanisms for a series of chemically distinct transformations. The Kinugasa reaction for the synthesis of beta-lactams was investigated. A novel retrocycloaddition step accounts mechanistically for byproducts associated with the transformation. A telescoped synthesis yielding cyanoimidazoles via combining an imidazole forming condensation annulation with a functional group conversion was also investigated. A series of Buchwald-Hartwig aminations performed within a glovebox using various aryl halide components were explored. Lastly, the mechanism of a synthetic procedure to synthesize Spiro-OMeTAD, a state-of-the-art organic material used in modern solar cells, was probed. By leveraging automated reaction monitoring devices, mechanistic understanding for each transformation was increased, ultimately making these transformations more efficient.
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Attribution-NonCommercial-NoDerivatives 4.0 International