General approach to spiroacenaphthylene pentacyclic systems: direct multicomponent assembling of acenaphthenequinone and cyclic carbonyl compounds with two molecules of malononitrile

A new type of catalytic cascade reaction was found: the direct multicomponent transformation of acenaphthenequinone, cyclic ketones, and two molecules of malononitrile into spiroacenaphthylene pentacyclic systems. The fast (5 min) reaction of acenaphthenequinone, cyclic ketones, and 2 equiv of malononitrile at ambient temperature results in the formation of pentacyclic and pentaheterocyclic spiroacenaphthylene frameworks in 70-95% yields. Thus, a new simple fast and efficient 'one-pot' method to synthesize substituted spiroacenaphthylene frameworks was found directly from simple starting compounds. The application of this convenient multicomponent method is also beneficial from the viewpoint of diversity-oriented large-scale processes.