Nikita O. Stepanov

Electrocatalysis in MIRC reaction strategy: facile stereoselective approach to medicinally relevant spirocyclopropylbarbiturates from barbituric acids and activated olefins

The combined electrolysis of barbituric acids and benzylidenemalononitriles or benzylidenecyanoacetates in methanol in an undivided cell in the presence of sodium bromide results in efficient MIRC (Michael-initiated ring-closure) formation of the corresponding spirocyclopropylbarbiturates in 45–93% yield. The electrocatalytic reaction proceeds smoothly under neutral and mild conditions with benzylidenemalononitriles or benzylidenecyanoacetates bearing both electron-donating and electron-withdrawing groups. NMR and single X-ray diffraction studies indicate that the electrocatalytic MIRC transformation of barbituric acids and benzylidenecyanoacetates results in the stereoselective formation of spirocyclopropanes with an (E)-configuration of aryl and alkoxycarboxylate substituents. The implication of electrocatalysis in the MIRC reaction strategy allows the combination of the synthetic virtues of both methods and accounts for an efficient approach to medicinally relevant spirocyclopropylbarbiturates avoiding inconvenient direct use of molecular halogen or halogenated substrates in accordance with the concepts of modern green chemistry.

New Way to Substitute Tetracyanocyclopropanes: One-Pot Cascade Assembling of Carbonyls and Malononitrile by the Only Bromine Direct Action

The new type of the chemical cascade reaction was found: formation of cyclopropanes from carbonyl compounds and CH acid by the only bromine direct action. The action of aqueous bromine on the carbonyl compounds and malononitrile in EtOH-H2O solutions in the presence of NaOAc results in the formation of 3-substituted 1,1,2,2-tetracyanocyclopropanes in 48–93% yields. The latter are well-known precursors for the different bicyclic heterosystems, among them those containing cyclopropane ring and those possessing different types of pharmacological activity.