It is well‐known that solvent is one of the most important factors that affect chemical reactions. This factor is more noticeable and impressive in the asymmetric reactions where the effective interaction of reactants and the creation of a uniform chiral environment is necessary. Nevertheless, when reactions are carried out in the absence of solvent, some privileged advantages such as easy work up, short reaction time, lack of waste solvents, and following the green chemistry principles, are appeared. Therefore, according to the importance of asymmetric synthesis and green chemistry, solvent‐free asymmetric catalysis can act as a considerable and necessary subject in synthetic chemistry. In this review, we have a survey on the solvent‐free asymmetric synthesis by the use of either homogeneous or heterogeneous chiral catalysts.

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A green and efficient method for the preparation of 5-aryl-4-hydroxy-2-methyl-1H-pyrrole-3-carboxylic acid esters and 6-aryl-3-methylpyridazine-4-carboxylic acid esters via threecomponent reaction of arylglyoxal hydrates with β-dicarbonyl compounds in the presence of ammonium acetate and hydrazine hydrate using water as solvent under ultrasonic irradiation was reported. The reactions proceeded rapidly and afforded the corresponding pyrroles and pyridazines in good to high yields in very short reaction time.

A novel and facile synthetic route for CMK‐3 type N‐rich ordered mesoporous carbon from cheap egg yolk biomass as a carbon precursor (EYCP) and SBA‐15 as a hard structure directing agent has been developed. To obtain a well‐ordered material, carbonization temperature was investigated. The N2 adsorption‐desorption analysis proved that the synthetic mesoporous carbon material at 500 °C is highly ordered, with high surface area of 226 m2 g−1, and nitrogen content of 6.2% was determined by CHN analysis. Corresponding mesoporous materials were examined as bifunctional acid‐base organocatalysts in a one‐pot tandem deacetalization‐Knoevenagel reaction. Results showed that the modified carbon material which was synthesized at 500 °C exhabited high nitrogen content and reactivity in one‐pot deacetalization‐Knoevenagel reaction. Carboxylic acid and pyridinic nitrogen groups of carbon material play as a bifunctional acid and base catalyst.