β-Boration of α,β-unsaturated carbonyl compounds in ethanol and methanol catalyzed by CCC-NHC pincer Rh complexes

•A pincer complex catalyzed 1-4-addition reactions at room temperature.•Cyclic and acyclic enone substrates were reactive under optimized conditions.•Eco-friendly solvents were applicable with air- and water-stable CCC-NHC pincer Rh complexes.

Quantitative β-boration of α,β-unsaturated carbonyl compounds was achieved utilizing the eco-friendly solvent EtOH along with MeOH at room temperature in 1 h, by a CCC-NHC pincer Rh complex mixture. Substrates with β-substituents were successfully converted yielding challenging, quaternary C–B bonds. The air- and water-stable pre-catalyst A, identified as a mixture of iodo and chloro CCC-NHC pincer Rh amine complexes, was evaluated for catalytic activity. This report is the first example of a pincer Rh complex demonstrating catalytic activity in a 1,4-addition at room temperature.

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