Solvent‐Free and Catalysts‐Free Chemistry: A Benign Pathway to Sustainability

Abstract

In the past decade, alternative benign organic methodologies have become an imperative part of organic syntheses and chemical reactions. The various new and innovative sustainable organic reactions and methodologies using no solvents or catalysts and employing alternative energy inputs such as microwaves, sonication, conventional and room temperature heating conditions, mechanochemical mixing, and high-speed ball milling are discussed in detail. Environmentally benign and pharmaceutically important reactions such as multicomponent, condensation, and Michael addition reactions; ring opening of epoxides; and oxidation and other significant organic reactions are discussed. An overview of benign reactions through solvent- and catalyst-free (SF-CF) chemistry and a critical perspective on emerging synergies between SF-CF organic reactions are discussed.

Magnetic nickel ferrite nanoparticles as an efficient catalyst for the preparation of polyhydroquinoline derivatives under microwave irradiation in solvent-free conditions

“…In recent years, the organic reactions on solid supports in the absence of a solvent and in solvent-free conditions have received considerable attention of synthetic chemists because of their high efficiency, environmentally benign conditions, convenient workup procedures, enhanced selectivity, milder reaction conditions, much improved reaction rates and formation of cleaner products [48]. Aiming to use these advantages, we planned to develop a solvent-free protocol for synthesis of polyhydroquinoline derivatives in solvent-free conditions.…”

Eco-friendly one-pot, three-component synthesis of novel derivatives of kojic acid by the Mannich-type reaction under solvent-free ball-milling conditions

“…1) [19][20][21][22][23][24]. However, a literature survey shows that most reported articles of Mannich reactions concern the study of kojic acid, To the best of our knowledge, there are no reports on three-component coupling of kojic acid, aromatic aldehydes and heteroaromatic amines to produce a new class of kojic acid derivatives as novel Mannich bases. In recent years, the use of ball-milling (intense mechanical grinding) as an efficient and green tool in organic synthesis has garnered great interest [25][26][27][28][29][30][31][32]. In addition to numerous organic classical reactions, some MCRs have also been performed using the ball-milling method [33,34].…”

Iodine-catalyzed Transformation of Aryl-substituted Alcohols Under Solvent-free and Highly Concentrated Reaction Conditions

“…[1][2][3] Transformations of neat reactants under solvent-free reaction conditions (SFRC) are one of the best solutions in this regard. [4][5][6][7] In the solid/solid system, a remarkable reaction rate enhancement was observed just by introducing small amounts of solvent vapor into the reaction mixture. 8 Moreover, the course of the reaction can be dramatically influenced under highly concentrated reaction conditions (HCRC).…”