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Registration Number

0224U001257, 0120U104008 , R & D reports

Title

Development of continuous-flow approach of safe and scalable utilization of non-stabilized diazoalkanes as reagents for organic synthesis

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Head

Volochnyuk Dmytro M., Доктор хімічних наук

Registration Date

19-01-2024

Organization

Institute of Organic Chemistry NAS of Ukraine

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Using the UOSlab®FlowReactor D1000 flow reactor, we successfully optimized conditions for the safe generation of diazomethane with a productivity of up to 0.45 mol/hour from nitrosomethylurea with aqueous KOH solution. Using the UOSlab® FlowReactor UF365/450 flow photochemical reactor, a 'pseudo-telescopic' Arndt-Eistert homologation protocol for carbonic acids was developed. Within the study of the synthetic potential of diazoketones as stable-storage reagents, the limits of their application as surrogates for halogen ketones in heterocyclic chemistry was explored. It was shown that in a 'one-pot' protocol, corresponding AADDKs are convenient reagents for synthesizing various thiazoles in reactions with thioureas and thioamides, while preserving the configuration of the chiral center from the original amino acid. Diazoketones, derived from chiral α- and β-amino acids, were studied in a series of transition metals catalyzed transformations. Conditions were found for preparative Rh-catalyzed intramolecular transformation of diazoketones into corresponding azetidones and pyrrolidones with preservation of chirality. In the case of diazoketones derived from α-amino acids, it was possible to avoid the use of Rh by replacing the metal-catalytic activation step of the reaction with photochemical LED irradiation at the 450 nm wavelength. Combining the flow generation with diazomethane’s ability to react in 1,3- cycloadditions with electron-deficient alkenes made it possible to synthesize pyrazolines in quantities exceeding hundreds of grams and define the limits of application of this reaction. It was found that the reaction scope is limited by steric hindrances around the double C=C bond. The dependance of the stability and reactivity of the obtained 4,5-dihydro-3H-pyrazoles (Δ1-pyrazolines) on their structural features was also studied.

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Volochniuk Dmytro M.
Gaiday Oleksandr V.
Nosyk Pavlo S.
Pashenko Olexander Ye
Pendyuh Vyachislav V.
Rozhenko Oleksandr
Sergiy V. Ryabukhin
Slobodyanyuk Yevgen Yu.
Shuvakin Serhii I
Yakovleva Hanna

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2024-01-19