Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3.

Deep eutectic solvents (DESs) have gained attention as green and safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and ß-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily reproducible protocol to isolate the product without the use of any organic solvent was established, and the recyclability of the DES mixture was successfully investigated.

Ammonia borane as a reducing agent in organic synthesis.

Ammonia borane NH3·BH3 is considered a promising material for hydrogen storage and release, and is attracting increasing attention as a relatively inexpensive, atom economy-convenient and viable reagent for developing new green synthetic transformations. The present review offers a wide overview on the use of AB in the reduction of organic compounds, and highlights the versatility of this reagent, due to the possibility of modulating its activity employing different strategies, which include the use of transition metals, p-block species, organocatalysts and FLP systems.