UROP Proceedings 2020-21

School of Science Department of Chemistry 9 Structure Prediction with Genetic Algorithm Supervisor: SU Haibin / CHEM Student: ZOU Zhiyan / CHEM Course: UROP1100, Fall Synthesis planning is one of the research approaches at the frontier of chemistry, as well as medicine and pharmacy. Our research focus on the machine learning models in retrosynthesis systems, making it necessary the extraction scaffold reaction information. The process follows a well design workflow. After scaffold information extraction, reactions are clustered by their forming bonds and ligand classes in order to find the relationship between reactions and reaction types. At current progress of this project, we only focus on the single-step Nickel-catalysed reactions. Valuable properties and hidden trends for Cross-Coupling and addition reactions emerged for further analysis and ready for deep learning in synthesis planning. Development of New Catalytic Organic Processes Supervisor: SUN Jianwei / CHEM Student: YAN Qiaolin / CHEM Course: UROP1100, Spring The work of two subprojects is discussed in this report. In the first project, various catalysts were screened in the hope to selectively oxidize 1,2,4-trimethylbenzene to 2,3,5-trimethyl-1,4-benquinone or 2,3,5trimethylhydroquinone using hydrogen peroxide as a mild and green oxidant. Synthesis of vitamin E from 2,3,5-trimethylhydroquinone was also attempted. In the second project, different hydride sources and various chiral phosphoric acids were screened for the enantioselective synthesis of triarylmethane via the reductive dehydroxylation of triarylmethanol. Preparation of the identified optimal catalyst and further optimization of the reaction conditions is still ongoing. Development of New Catalytic Organic Processes Supervisor: SUN Jianwei / CHEM Student: LI Yuxuan / SSCI Course: UROP1000, Summer The direct enantioselective 1,6-addition of 5-methide-5H-indoles, generated in situ from corresponding diarylmethanols, has been attempted in the presence of chiral phosphoric acids (CPAs). Preliminary experiments using various nucleophiles with racemic phosphoric acid (RPA) have been carried out to select feasible reaction partners of diarylmethanols. To achieve the remote activation of the substrate and the enantioselectivity of the substitution reaction, evaluation of catalysts, solvents, concentration of reactants, and temperature have been performed. Furthermore, the modification of the diarylmethanols’ structure has also been attempted in hopes of achieving better enantioselectivity. Although such a reaction mode is currently not synthetically applicable because the enantioselectivity (ee value up to 56%) requires further enhancement, the efforts in condition optimization and substrate modification could be valuable for investigation of similar reactions.

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