Direct 2,2,2‐Trifluoro and 2,2‐Difluoroethoxylation of a Model Macrocyclic Ar−H Substrate via Ni‐Catalysis

Abstract

Abstract Herein, we describe the trifluoro‐ and difluoroethoxylation of C(sp2)‐H bonds using nickel(II) complexes incorporating a model macrocyclic arene substrate. Due to the coordinative properties of the macrocyclic substrate, we were able to detect and characterize the just‐formed C(sp2)−OCH2CF3−Ni(II) species by HRMS and IRPD. DFT studies on the C(sp2)−OCH2CF3 bond formation mechanism indicate that it involves a Ni(III)/Ni(I) reductive elimination followed by oxidation to Ni(II) rather than the higher energy barrier Ni(IV)/Ni(II) reductive elimination. This mechanistic investigation deepens the versatile redox abilities of Ni compounds and might help in designing new catalysts for the 2,2,2‐trifluoroethoxylation and 2,2‐difluoroethoxylation of arene C−H bonds.

Keywords

• Nickel organometallics
• C−H activation
• fluoroalkoxylation
• Ni(I)/Ni(III) redox catalysis
• He-tagging IRPD spectroscopy