Chemistry Research Collection

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Now showing 1 - 5 of 233
  • Publication
    Functional Group Interconversion Reactions in Continuous Flow Reactors
    An overview of the current uptake of continuous flow techniques for various functional group interconversion reactions is presented. Besides highlighting a variety of prominent examples and their main features, this review provides insights into specific reaction classes, such as oxidations, reductions, rearrangements as well as different C-H functionalization processes. While this review can only include key examples from the last decade, the reader will find a solid foundation of important transformations along with further references to inform and appreciate the opportunities arising from modern synthesis technologies such as flow synthesis.
    Scopus© Citations 4  160
  • Publication
    Overcoming the Hurdles and Challenges Associated with Developing Continuous Industrial Processes
    Continuous flow chemistry is often viewed as a very simple concept on paper, however scientists with significant flow chemistry experience will highlight a number of challenges that need to be overcome. Critical for the successful development of any flow process is a high level of understanding of potential pitfalls that may be encountered. A collaborative and multi-disciplinary team of chemists and chemical engineers is essential in the development of a process from lab scale through to production. This Minireview will identify and highlight relevant risks and their subsequent mitigation strategies to ensure successful flow processing.
    Scopus© Citations 31  34
  • Publication
    Continuous Flow Synthesis of Cyclobutenes Using LED Technology
    Cyclobutenes are highly strained ring systems of considerable synthetic interest that can be accessed via cycloaddition reactions between alkenes and alkynes. However, their traditional preparation relies on photochemical [2+2]-cycloadditions that exploit low wavelength UV radiation emitted from inefficient medium-pressure Hg-lamps. This paper reports on the development of a modern approach using a high-power LED set-up emitting at the boundary of UV-A and visible light in conjunction with a continuous flow reactor. The resulting flow process renders a series of cyclobutenes from maleimides and various commercial alkynes. This provides a more energy-efficient approach that is readily scalable to access multigram quantities of cyclobutenes in high chemical yields and short residence times. The value of these products is exemplified by flow-based hydrogenations yielding highly substituted cyclobutanes which represent sought after building blocks in modern medicinal chemistry programs.
      91
  • Publication
    Development of a Continuous Photochemical Benzyne-Forming Process
    A continuous-flow process is presented that enables the safe generation and derivatization of benzyne under photochemical conditions. This is facilitated by a new high-power LED lamp emitting light at 365 nm. The resulting flow process effectively controls the release of gaseous by-products based on an adjustable backpressure regulator and delivers a series of heterocyclic products in a short residence time of 3 minutes. The robustness of this methodology is demonstrated for the rapid generation of benzotriazoles, 2 H -indazoles and various furan-derived adducts, facilitating the preparation of these important heterocyclic scaffolds via a simple and readily scalable flow protocol.
      51Scopus© Citations 11
  • Publication
    Coupling biocatalysis with high-energy flow reactions for the synthesis of carbamates and β-amino acid derivatives
    A continuous flow process is presented that couples a Curtius rearrangement step with a biocatalytic impurity tagging strategy to produce a series of valuable Cbz-carbamate products. Immobilized CALB was exploited as a robust hydrolase to transform residual benzyl alcohol into easily separable benzyl butyrate. The resulting telescoped flow process was effectively applied across a series of acid substrates rendering the desired carbamate structures in high yield and purity. The derivatization of these products via complementary flow-based Michael addition reactions furthermore demonstrated the creation of β-amino acid species. This strategy thus highlights the applicability of this work towards the creation of important chemical building blocks for the pharmaceutical and speciality chemical industries.
      33