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Information × Registration Number 0221U106639, 0120U104008 , R & D reports Title Development of continuous-flow approach of safe and scalable utilization of non-stabilized diazoalkanes as reagents for organic synthesis popup.stage_title Head Volochnyuk Dmytro M., Доктор хімічних наук Registration Date 16-12-2021 Organization Institute of Organic Chemistry NAS of Ukraine popup.description2  Molecular structure, thermal stability of diazoketones, their tendency to decompose and transform into the corresponding ketene have been studied. During the reporting period, the structure of three diazoketones was detrmined by X-ray single crystal diffraction study. It is shown that the compounds are relatively stable, decomposition temperatures (110-142 °C) were determined for eight members of the diazoketone series. It was found that the stability of diazoketones is determined by the presence of a conjugation between π-systems C=N=N and a carbonyl group with a significant contribution of the resonant structure –C(O–)=C–N+ºN. This is evidenced by the results of quantum chemical calculations at the DFT approximation level performed for model structures of diazoketones. The most probable way of the first stage of thermal decomposition of diazoketones is the elimination of the nitrogen molecule with a synchronous rearrangement into the corresponding ketene. Decomposition enthalpy calculated for this process within the DFT approximation agrees well with the average decomposition enthalpy of ~ 100 kJ/mol reported in the literature. By combining the flow generation of diazomethane with its subsequent [3+2]-cycloaddition to electron-deficient alkenes, for the first time it was possible to obtain the corresponding pyrazolines in quantities exceeding one hundred grams. The limits of application of this reaction are defined. It was found that the flow-initiated decomposition of pyrazolines leads to the formation of the corresponding cyclopropanes. The reaction is stereoselective, the structure of the formed cyclopropane is determined by the configuration of the starting alkene. Relevant new compounds have been isolated and characterized. A protocol for the synthesis of heme-difluorocyclopropenes by slow addition of Ruppert-Prakash reagent was developed. The approach is convenient and preparative, suitable for a wide range of functional groups and further scaling. A wide s Product Description popup.authors Volochnyuk Dmitro M. Gaidai Oleksandr Vasyliovich Pashchenko Ye. O. Pendyuh Vyachislav V. Rozhenko Oleksandr B. Slobodianiuk Yevhenii Yuriiovych Turyk Bogdan Anatoliyevich Shuvakin Sergiy I. popup.nrat_date 2021-12-16 Close