With the growing interest in renewable energy and global warming, it is important to minimize the usage of hazardous chemicals in both academic and industrial research, elimination of waste, and possibly recycle them to obtain better results in greener fashion. The studies under the area of mechanochemistry which cover the grinding chemistry to ball milling, sonication, etc. are certainly of interest to the researchers working on the development of green methodologies. In this review, a collection of examples on recent developments in organic bond formation reactions like carbon–carbon (C–C), carbon–nitrogen (C–N), carbon–oxygen (C–O), carbon–halogen (C–X), etc. is documented. Mechanochemical syntheses of heterocyclic rings, multicomponent reactions and organometallic molecules including their catalytic applications are also highlighted.
An unprecedented C-H mononitration of indolines either at the -C or -C positions under mild condition is reported here. The roles of multiple weak interactions and factors such as steric factors, electronic effects, cation-π interactions, and solvent polarity were established, and we achieved a 100% regioselective electrophilic aromatic (EArS) nitration using Cu(NO) or AgNO.
The reaction of methylviologen iodide with crystalline V2O5 in the molar ratio of 1 to 3.8 at 100 degrees C in water led to the formation of (MV)0.25V2O5 in quantitative yield. The structure of this organic-inorganic multilayered hybrid compound was determined by single-crystal X-ray crystallography. Strong van der Waals interactions were found between the electron-deficient aromatic organic molecules and the inorganic layers. In the solid state, the compound is a semiconductor due to small polaron hopping and shows novel reversible alkali-ion intercalation/deintercalation via electrochemistry.
Development of sustainable methods for the activation of less reactive undirected C(sp3)–H bonds is challenging but desired in organic synthesis. The present manuscript demonstrates selective activation of acidic C(sp3)–H groups for a dehydrogenative C–H imination reaction by 4H elimination using PhI (10 mol%)–mCPBA as an organocatalyst.
We report here an understanding of systems chemistry on small molecules through covalent mechanochemistry. As a proof‐of‐concept, the multicomponent Biginelli reaction by subcomponent synthesis was considered as a model system. Reactions were performed under solvent‐free, metal‐free, mechanochemical (ball milling) and ambient laboratory conditions. Br+‐catalyzed oxidation of benzyl alcohols led to the product benzaldehydes and byproduct H+ which were further promoted as component and catalyst, respectively, for a cascade transformation to dihydropyrimidones within the same reaction pot. Remarkably, in solution, the reaction system could not be reproduced at room temperature even after 24 h.
The urge to use alternative energy sources has gained significant attention in the eye of chemists in recent years. Solution-based traditional syntheses are extremely useful, although they are often associated with certain disadvantages like generation of waste as by-products, use of large quantities of solvents which causes environmental hazard, etc. Contrastingly, achieving syntheses through mechanochemical methods are generally time-saving, environmentally friendly and more economical. This review is written to shed some light on supramolecular chemistry and the synthesis of various supramolecules through mechanochemistry.
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