Microwave-Assisted Multicomponent Reactions in the Heterocyclic Chemistry

The use of emerging multicomponent reactions (MCRs) in conjunction with microwave (MW)-assisted chemistry techniques is dramatically reducing chemical waste and reaction times in several organic syntheses and chemical transformations. The MW-assisted MCRs offer rapid and efficient procedures for the introduction of many points of structural diversity into heterocyclic compounds prepared in a straightforward manner in a single synthetic step. The present review summarizes recent developments in MW-assisted MCRs for the construction of five-, six-, and seven-membered heterocyclic skeletons as well as dicyclic system. Methods for the generation of both simple and fused heterocyclic targets are described, with particular emphasis on the introduction of structural diversity and complexity. In many cases, MW-assisted MCRs offer considerable improvements in selectivity, chemical yield and purity and constitute a very simple and extremely rapid method to access a diverse range of heterocyclic motifs.