[reaction: see text] A task-specific ionic liquid, [bmIm]OH, has been introduced as a catalyst and as a reaction medium in Michael addition. Very interestingly, although the addition to alpha,beta-unsaturated ketones proceeds in the usual way, giving the monoaddition products, this ionic liquid always drives the reaction of open-chain 1,3-dicarbonyl compounds with alpha,beta-unsaturated esters and nitriles toward bis-addition to produce exclusively bis-adducts in one stroke.

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A highly chemoselective reduction of aromatic nitro compounds to the corresponding amino derivatives has been achieved by a combination of copper nanoparticles and ammonium formate in ethylene glycol at 120 degrees C. The reductions are successfully carried out in presence of a wide variety of other reducible functional groups in the molecule, such as Cl, I, OCH2Ph, NHCH2Ph, COR, COOR, CN, etc. The reactions are very clean and high yielding.

The carbon-carbon and carbon-heteroatom bond formations constitute the backbone of organic synthesis and have been widely used in the synthesis of natural products and useful compounds. Because of growing environmental concern, more attention has been focussed on the development of greener methods. Copper is environment-friendly and comparatively inexpensive. Although the use of copper salts in catalysis has been known since the last century, this area of research has been less explored compared to other metals, such as palladium, magnesium, and zinc. This review highlights the general features of nanoparticles as catalysts with particular reference to copper and the recent developments in the copper(0) nanoparticle-catalyzed C(aryl)-C(aryl/alkynyl), C(aryl)-N, C(aryl)-O, C(aryl)-S, and C(aryl)-Se bond formations and related reactions. The mechanisms of the reactions have been outlined and discussed with respect to the active catalytic species and possible intermediates. The scope, limitations, and green aspects of the reactions have also been highlighted. The convenient methods of preparation of copper nanoparticles and their characterization are described.

A simple and efficient procedure for the rearrangement of substituted epoxides catalyzed by InCl3 has been developed. Aryl-substituted epoxides isomerize with complete regioselectivity to form a single carbonyl compound via cleavage of the benzylic C−O bond. The reactions are simple, fast, and high yielding. This procedure is very mild compared to those catalyzed with BF3 and other Lewis acids and compatible with several acid-sensitive functionalities. This protocol provides a highly selective synthesis of substituted benzylic aldehydes and ketones. However, rearrangement of alkyl-substituted epoxides is not very selective.