Browsing by Author "Darren J. Derksen"

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    A vinylogous Norrish reaction as a strategy for light-mediated ring expansion
    (Royal Society of Chemistry, 2022-02-03) Evgueni Gorobets; James W. Papatzimas; Jorge Dourado; Goonay Yousefalizadeh; JinGyu Lee; Duncan K. Brownsey; Kevin Stamplecoskie; Rebecca Davis; Darren J. Derksen
    The reactions of bicyclic divinyl ketones display wavelength-dependent changes in product formation. UV irradiation results in the formation of competitive and tricyclic unsaturated ketones that subsequently undergo ring expansion and reaction with a range of nucleophiles. DFT calculations and transient absorption experiments were completed that are consistent with a vinylogous Type II Norrish pathway.
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    Generation of Benzyne Species from Diphenylphosphoryl Derivatives: Simultaneous Exchange of Three Functional Groups
    (European Chemical Societies Publishing, 2016-05-16) Evgueni Gorobets; Masood Parvez; Darren J. Derksen; Brian A. Keay
    Interaction of (2‐diphenylphosphoryl‐3‐iodo‐4‐methoxy‐phenyl) methanol with NaH in DMF at ambient temperature results in the generation of benzyne intermediates that can be trapped by furan or DMF. Trapping with DMF forms 3‐(dimethylaminomethyl)‐2‐hydroxy‐6‐methoxybenzaldehyde demonstrating the simultaneous exchange of three functionalities in a single step. The presence of the alkoxy substituent adjacent to iodine is critical for high regioselectivity addition of DMF. The corresponding bromide or triflate can be used in place of the iodide with equal efficiency. This methodology was used to synthesize the reported structure of gigasol and leading to a structural reassignment of this biscoumarin natural product.
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    Regioselective Synthesis of C3-Hydroxyarylated Pyrazoles
    (American Chemical Society, 2021-12-14) Leonie O’Sullivan; Ketul V. Patel; Ben C. Rowley; Duncan K. Brownsey; Evgueni Gorobets; Benjamin S. Gelfand; Jeffrey F. Van Humbeck; Darren J. Derksen
    Pyrazoles are ubiquitous structures in medicinal chemistry. We report the first regioselective route to C3-hydroxyarylated pyrazoles obtained through reaction of pyrazole N-oxides with arynes using mild conditions. Importantly, this method does not require the C4 and C5 positions of the pyrazole to be functionalized to observe regioselectivity. Using this method, we completed the synthesis of a recently reported JAK 1/2 inhibitor. Our synthesis produces the desired product in 4 steps from commercially available starting materials.