Hydrogenative coupling of nitriles with diamines to benzimidazoles using lignin-derived Rh2P catalyst
Jiarui Zhang,
Ruxu Yao,
Jinzhu Chen,
Tao Li,
Yisheng Xu
Affiliations
Jiarui Zhang
State Key Laboratory of Chemical Engineering, International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; College of Chemistry and Materials Science, Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 511443, China
Ruxu Yao
State Key Laboratory of Chemical Engineering, International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; College of Chemistry and Materials Science, Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 511443, China
Jinzhu Chen
College of Chemistry and Materials Science, Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 511443, China; Corresponding author
Tao Li
State Key Laboratory of Chemical Engineering, International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; Corresponding author
Yisheng Xu
State Key Laboratory of Chemical Engineering, International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; Corresponding author
Summary: Nitrile (C≡N bond) activation for direct organic synthesis has been less explored so far due to a high redox potential of nitrile and its low dissociation energy of C−CN bond. Herein, we demonstrate a direct reductive coupling of nitriles and 1,2-phenylenediamines to yield various benzimidazoles in excellent yields (95%–99%) by using rhodium phosphide (Rh2P) catalyst supported on lignin-derived carbon (LC) using H2 (or hydrazine hydrate) as a hydrogen source. The high catalytic performance of Rh2P/LC is attributed to enhanced charge transfer to Rh and strong P−Rh interactions. Our isotope trace experiment confirms the presence of H/D exchange between H2 and the inert –CD3 group of CD3CN via an intramolecular D-shift. Reusability of Rh2P/LC is further demonstrated by a seven-time recycling without evident loss of activity. This research thus highlights a great potential in organic transformation with nitrile as a synthetic building block.
