New Nickel-Based Catalytic System with Pincer Pyrrole-Functionalized N-Heterocyclic Carbene as Ligand for Suzuki-Miyaura Cross-Coupling Reactions

A new catalytic system with Ni(NO3)(2)center dot 6H(2)O as the catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as the ligand was employed in the Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids. With 5 mol% catalyst, the catalytic reactions proceeded at 160 degrees C, giving coupling products in isolated yields of up to 94% in short reaction times (1-4 h). The system worked effi-ciently with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups. Steric effects were observed for both aryl iodides and arylboronic acids. It is proposed that the reactions underwent a Ni(I)/Ni(III) catalytic cycle. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The new catalytic system using Ni(NO3)(2)center dot 6H(2)O as catalyst and a pincer pyrrole-functionalized N-heterocyclic carbene as ligand showed high efficiency in Suzuki-Miyaura cross-coupling reactions of aryl iodides with arylboronic acids, yielding high isolated yields of coupling products in short reaction times. The system worked well with aryl iodides bearing electron-donating or electron-withdrawing groups and arylboronic acids with electron-donating groups, while steric effects were observed for both aryl iodides and arylboronic acids.