Malononitrile dimer as a privileged reactant in design and skeletal diverse synthesis of heterocyclic motifs

Malononitrile dimer as a precursor reactant has been extensively applied in the diversity-oriented synthesis of various heterocyclic motifs, bis-heterocyclic compounds, fused heterocycle derivatives, bicyclic bridged heterocyclic scaffolds, and highly substituted carbocyclic compounds. These remarkable products were synthesized via various types of reactions, such as cycloaddition, cyclocondensation, cascade/domino/tandem reactions along with multi-component reactions. In addition, the flexibility and high reactivity of malononitrile dimer as a multi-functional reagent and its potential to the preparation of novel beneficial scaffolds as well as biologically active molecules signify it as a suitable building block in total synthesis, medicinal chemistry, and dyes. In the present review, the advances in the chemistry of malononitrile dimer as a potent reagent in organic synthesis have been reported in the past to now.