Abstract

This study describes the palladium-catalyzed chemoselective1 amination of chloroaryl triflates in the C−Cl bond for the first time. A newly designed and synthesized alkyl-pyrazole-based phosphine ligand, L26 (BirdPhos), which is featured with the pyrazole ligand core and the cyclohexyl group at the C3 and C5 positions, was key to the success of this reaction. A variety of chloroaryl triflates coupled with aromatic, aliphatic, and heterocyclic amines smoothly afforded the corresponding products up to 97% yields with averaged chemoselectivity of 99.7% in the C−Cl bond. This study attempts to investigate the structure-activity relationship of this new class of ligand through experimental and density functional theory (DFT) calculations.

Reference:

1. a) So, C. M.; Yuen, O. Y.; Ng, S. S.; Chen, Z. ACS Catal. 2021, 11, 7820-7827; b) Wang, M.; So, C. M.; Org. Lett. 2022, 24, 681-685; c) Chen, Z.; Gu, C.; Yuen, O. Y.; So, C. M. Chem. Sci. 2022,13, 4762-4769.