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Palladium‐Catalyzed Cross‐Coupling of 2‐Chloroquinoxaline N ‐Oxides with Arylboronic Acids
Author(s) -
Maichrowski Jan,
Hübner Eike G.,
Kaufmann Dieter E.
Publication year - 2013
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201300707
Subject(s) - chemistry , catalysis , palladium , amide , annulation , steric effects , coupling reaction , alkylation , combinatorial chemistry , organic chemistry , medicinal chemistry , reaction conditions
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.