The catalytic hydration of 1,2-, 1,3- and 1,4-dicyanobenzenes using nickel(0) catalysts

The homogeneous catalytic hydration of 1,2-, 1,3- and 1,4-dicyanobenzenes using organometallic nickel(0) catalysts of general formula [(dippe)Ni(η2-N,C-1,n-(CN)2-benzene)] (n = 2–4; complexes 2–4, respectively) was achieved under heating, the products of hydration, at least in the case of 1,3- and 1,4-dicyanobenzene being strongly dependent on the temperature used for the process; the production of the respective 1,3- and 1,4-cyanobenzamides been observed at 120 °C, while catalysis at 180 °C resulted in the quantitative formation of the 1,3- and 1,4-dicarboxylic acids. In the case of 1,2-dicyanobenzene, catalysis at either temperature yielded the hemihydration product 1,2-phthalamide, implying an important difference in overall reactivity for this system. All the hydration products were obtained in excellent selectivity and yield, using 0.5 mol% loadings of the corresponding nickel(0) catalyst and thus, the current work provides important evidences that could be of use for both synthetic organic chemistry and in the eventual production of polyamides.

Graphical abstractThe homogeneous catalytic hydration of 1,2-, 1,3- and 1,4-dicyanobenzenes was achieved under heating using organometallic nickel(0) catalysts of general formula [(dippe)Ni(η2-N,C-1,n-(CN)2-benzene)]. Figure optionsDownload full-size imageDownload as PowerPoint slide