Selective cross-coupling of α,β-unsaturated nitriles with aldehydes or alcohols by hydrogen transfer catalysis towards β-ketonitriles and glutaronitriles

Abstract

β-Ketonitriles and glutaronitriles are both valuable compounds in the chemical and pharmaceutical industries. We report here a novel ruthenium-catalyzed selective cross-coupling of α,β-unsaturated nitriles with aldehydes or alcohols towards β-ketonitriles and glutaronitriles via hydrogen transfer catalysis. Branch-selective hydroacylation of the feedstock chemical acrylonitrile and its derivatives produces versatile β-ketonitriles using a wide range of non-chelating aldehydes or alcohols. Moreover, functionalized glutaronitriles have been obtained via cross-coupling of acrylonitrile and alcohols through a one-step tandem hydroacylation and Michael addition reaction. Mechanistic studies reveal that the reaction takes place via hydrogen transfer catalysis through a possible keteniminate ruthenium intermediate.