Furfural and 5-(hydroxymethyl)furfural valorization using homogeneous Ni(0) and Ni(II) catalysts by transfer hydrogenation

The complex [dippeNi(COD)] (dippe =1,2-bis(diisopropyl phosphino)ethane) was used as a catalytic precursor in furfural (FF) and 5-(hydroxymethyl)furfural (HMF) valorization, along with formic acid as hydrogen transfer agent, to produce the corresponding alcohol in each case, with excellent yields (≥99%) and under mild conditions (5 h, 120 °C). The air-stable Ni(II)-catalyst precursor, [dippeNiCl2], was assessed in FF hydroamination, with a variety of anilines, using FA as hydrogen source (at 16 h and 120 °C), to produce furfuryl amines with an excellent yield and selectivity (89 to >99%). To our knowledge, this is the first report of reductive amination of FF to get furfuryl amines using a homogeneous Ni catalyst in a hydrogen transfer protocol.