Ruthenium‐Catalyzed α‐Alkylation of Arylacetonitriles with Primary Alcohols: N ‐heterocyclic Carbene‐Amine's Promotional Influence

Abstract Transition‐metal‐catalyzed α‐alkylation of nitriles with alcohols is an environmentally benign reaction, and the development of simple and efficient catalysts for this transformation is a growing area of research. In this study, we report a serial of bidentate N ‐heterocyclic carbene (NHC) ruthenium complexes with different extra donors for the α‐alkylation of nitriles with alcohols. Through adjusting extra donors and backbone of the NHC ligands, the catalytic activities of these complexes could be controlled. The ruthenium complex ( Ru3 ) bearing an amine donor and a benzimidazolium backbone exhibited the highest catalytic activity. A large variety of α‐alkylated nitriles were obtained in 30%–88% yields, by using 1 mol% ruthenium complex ( Ru3 ) and a catalytic amount of Cs 2 CO 3 (20 mol%). Detailed control experiments and deuterium‐labeling experiments suggested that the reaction proceeds via borrowing hydrogen pathway.