Four‐Component Borocarbonylation of Vinylarenes Enabled by Cooperative Cu/Pd Catalysis: Access to β‐Boryl Ketones and β‐Boryl Vinyl Esters

We report here a general four‐component synthetic procedure for the preparation of β‐boryl ketones and β‐boryl vinyl esters. Joint catalyzed by palladium and copper catalysts, borocarbonylative reaction between vinylarenes, aryl halides/triflates, B2Pin2, and carbon monoxide proceed successfully. A variety of synthetically useful β‐boryl ketones were synthesized in good to high yields by using aryl iodides as the substrates. It is noteworthy that when aryl triflates were applied as the starting materials, β‐boryl vinyl esters were synthesized in a similar manner and with broad functional group tolerance. A rational mechanism for this reaction was also proposed. Joint catalysis: The cooperative Cu/Pd‐catalyzed four‐component borocarbonylation of vinylarenes, aryl halides/triflates, B2Pin2, and CO generates β‐boryl ketones and β‐boryl vinyl esters in good to high yields. A rational mechanism was proposed for the synthesis of β‐boryl vinyl esters, which involves an acyl‐copper intermediate in the Cu cycle.