Electrochemical cascade assembling of heterocyclic ketones and two molecules of malononitrile: facile and efficient ‘one-pot’ approach to 6-heterospiro[2.5]octane-1,1,2,2-tetracarbonitrile scaffold

The electrochemically induced reaction of heterocyclic ketones and two equivalents of malononitrile in an undivided cell in alcohols in the presence of sodium bromide as mediator leading to the selective formation of substituted 6-heterospirocyclopropane-1,1,2,2-tetracarbonitriles in 50–75% yields as a result of the complex cascade process has been investigated. This new electrocatalytic cascade process smoothly proceeds with different types of heterocyclic ketones and resulted in ‘one-pot’ formation of 6-heterospirocyclopropane-1,1,2,2-tetracarbonitriles with prominent pharmacological and physiological activity. The application of this electrochemical cascade method to the formation of medicinally relevant substituted 6-heterospiro[2.5]octane-1,1,2,2-tetracarbonitriles is also beneficial from the viewpoint of diversity-oriented large-scale processes.