Direct and rapid heating by microwave irradiation in combination with sealed vessel processing in many cases enables reactions to be carried out in a fraction of the time generally required using conventional conditions. This makes microwave chemistry an ideal tool for rapid reaction scouting and optimization of conditions, allowing very rapid progress through hypotheses–experiment–results iterations. The speed at which multiple variations of reaction conditions can be performed allows a morning discussion of “What should we try?” to become an after-lunch discussion of “What were the results” Not surprisingly, therefore, many scientists both in academia and industry have turned to microwave synthesis as a front-line methodology for their projects. In this review, more than 220 published examples of microwave-assisted synthetic organic transformations from the 2004 to 2008 literature are discussed. An additional ca. 500 reaction schemes are presented in the Electronic Supplementary Material, providing the reader with an overall number of ca. 930 references in this fast-moving and exciting field.

Controlled microwave heating in modern organic synthesis: highlights from the 2004–2008 literature

Metal-Free Multicomponent Syntheses of Pyridines

Multicomponent domino reactions (MDRs) serve as a rapid and efficient tool for the synthesis of versatile heterocycles, particularly those containing structural diversity and complexity, by a one-pot operation. These reactions can dramatically reduce the generation of chemical wastes, costs of starting materials, and the use of energy and manpower. Moreover, the reaction period can be substantially shortened. This Review covers recent advances on multicomponent domino reactions for the construction of five-, six-, and seven-membered heterocyclic skeletons and their multicyclic derivatives.

Multicomponent Reactions for the Synthesis of Heterocycles

Deep eutectic solvents (DESs) as eco-friendly and sustainable solvent/catalyst systems in organic transformations

A new four-component domino reaction has been discovered. The reaction is easy to perform simply by mixing four common reactants and K2CO3 in ethylene glycol under microwave irradiation. The reaction proceeds rapidly and can be finished within 10−24 min with water as the major byproduct, making workup convenient. Four stereogenic centers with one quaternary carbon−amino function are controlled very well; the stereochemistry was unequivocally determined by X-ray structural analysis. The resulting pyrido[3,4-i]quinazoline derivatives are of importance for organic and medicinal research.

Four-Component Domino Reaction Leading to Multifunctionalized Quinazolines

A series of unusual fused heterocyclic compound derivatives, consisting of a pyridine and a imidazole or pyrimidine core, with a bridgehead nitrogen, were successfully synthesized by a microwave-assisted, three-component domino reaction of aldehydes, enaminones, and malononnitrile. In this one-pot reaction, up to five new bonds were formed accompanied by generating the lactam group. This method has the advantages of short synthetic route, operational simplicity, increased safety for small-scale high-speed synthesis, and minimal environment impact.

Microwave-assisted combinatorial synthesis of polysubstituent imidazo[1,2-a]quinoline, pyrimido[1,2-a]quinoline and quinolino[1,2-a]quinazoline derivatives.

A novel three-component reaction for the synthesis of new 4-azafluorenone derivatives

A facile and selective synthesis of poly-substituted pyrido[2,3- D]pyrimidines is accomplished via microwave-assisted multicomponent reactions controlled by the nature of solvent. In addition, a possible mechanism accounting for the reaction is proposed.

Chunmei Li

Papers

Microwave-assisted combinatorial synthesis of polysubstituent imidazo[1,2-a]quinoline, pyrimido[1,2-a]quinoline and quinolino[1,2-a]quinazoline derivatives.

A novel three-component reaction for the synthesis of new 4-azafluorenone derivatives

An Efficient Chemoselective Synthesis of Pyrido[2,3-d]pyrimidine Derivatives under Microwave Irradiation

An efficient synthesis of pyrido[2,3-d]pyrimidine derivatives and related compounds under ultrasound irradiation without catalyst.

Green and high efficient synthesis of triaza‐benzo[b]fluoren‐6‐one derivatives in water under microwave irradiation