Simple and facile electrocatalytic approach to medicinally relevant spirocyclopropylpyrazolones directly from pyrazoline-5-ones and activated olefins

The electrolysis of pyrazoline-5-ones and activated olefins in the presence of sodium bromide as mediator in alcohols in an undivided cell results in efficient formation of the substituted spirocyclopropylpyrazolones in 50-85 % yields. This novel electrocatalytic process opens a convenient way to functionalized spirocyclopropylpyrazolones-the promising compounds for the different biomedical applications. Thus, the simple electrocatalytic system can produce in an undivided cell under mild conditions the electrochemically induced cascade reaction of pyrazoline-5-ones with activated olefins.