Palladium‐Catalyzed Cross‐Coupling of 2‐Chloroquinoxaline N‐Oxides with Arylboronic Acids

Abstract

A selection of 2‐chloro‐substituted O‐alkylquinoxaline N‐oxides, easily accessible by the one‐step annulation reaction of 4‐fluoroaniline with 1,1,2‐trichloro‐2‐nitroethylene and subsequent O‐alkylation, was arylated at the chloronitrone unit in yields up to 96 %. This first efficient Pd‐catalyzed Suzuki–Miyaura reaction of chloroquinoxaline N‐oxides with arylboronic acids led to new 2‐arylquinoxaline N‐oxides. The scope and limitations of this arylation reaction were investigated, and the role of some sterically demanding boronic acids in the cross‐coupling reaction was evaluated by means of DFT calculations. Additionally, the Pd‐catalyzed C‐arylation of the amide unit of selected quinoxalinone derivatives was accomplished.