Consecutive multicomponent reactions (MCRs) combine two or more MCRs to achieve high synthetic efficiency, product structural diversity, and molecular complexity.

A novel magnetic nanoparticle supported basic ionic liquid was successfully prepared by covalently anchoring 1-(2′-piperidyl)ethyl-3-(3-propyltriethoxysilane)imidazolium chloride onto the surface of silica-coated Fe₃O₄ nanoparticles, and characterized by FT-IR, TEM, XRD, TGA, VSM and elemental analysis. The obtained supported ionic liquid was certified as a versatile and robust catalyst for the unsymmetrical Hantzsch reaction and Knoevenagel condensation under solvent-free conditions. Furthermore, the catalyst could be conveniently recovered by an external magnet and reused six times without significant loss of catalytic activity.

A [4 + 2] annulation involving cascade Knoevenagel, aza-Wittig and dehydrofluorination reactions is developed for the synthesis of substituted quinolin-4-ols including analogs bearing CF₂H, CF₃, and C₂F₅ groups. This simple and highly efficient method is also applicable for the synthesis of substituted quinolines. A number of reported biologically active compounds can be readily prepared by this one-pot synthesis. Green chemistry metrics analysis of the new reaction processes provided favorable results.

A new synthetic method for diastereoselective synthesis of tetrahydro-pyrrolo[1,2-d][1,4]benzodiazepines and tetrahydro-pyrrolo[1,2-d][1,4]diazepinones is developed which involves 1,3-dipolar cycloaddition, N-alkylation or N-acylation and Staudinger/aza-Wittig reactions. This one-pot and three-step synthesis of four components gave two different heterocyclic scaffolds. Green chemistry metrics analysis of the reaction process provided favorable results.

Multicomponent reactions (MCRs) have inherent advantages in pot, atom, and step economy (PASE). This important green synthetic approach has gained increasing attention due to high efficiency, minimal waste, saving resources, and straightforward procedures. Presented in this review article are the recent development on 5-compoment reactions (5CRs) of the following six types: (I) five different molecules A + B + C + D + E; pseudo-5CRs including (II) 2A + B + C + D, (III) 2A + 2B + C, (IV) 3A + B + C, (V) 3A + 2B, and (VI) 4A + B. 5CRs with more than five-reaction centers are also included.