Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3

Beilstein J Org Chem. 2021 May 6:17:1041-1047. doi: 10.3762/bjoc.17.83. eCollection 2021.

Abstract

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 β-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.

Keywords: DES; alternative solvents; atom economy; nitro derivatives; reduction.

Grants and funding

M. B. thanks MUR for the project PRIN 2017 “NATURECHEM. M. B. thanks Università degli Studi di Milano for the PSR 2019-financed project “Catalytic strategies for the synthesis of high added-value molecules from bio-based starting material”. M. B. and P. C. G. thank the ITN-EID project Marie Skłodowska-Curie Actions Innovative Training Network–TECHNOTRAIN H2020-MSCA-ITN-2018 Grant Agreement 812944. http://www.technotrain-ITN.eu.