Copper-catalyzed synthesis of benzoxazoles via a regioselective C-H functionalization/C-O bond formation under an air atmosphere.
An efficient method for the synthesis of functionalized benzoxazoles is described that involves a copper(II)-catalyzed regioselective C-H functionalization/C-O bond formation protocol. The use of dichlorobenzene as a solvent at 160 degrees C allows the use of air as the terminal oxidant in the catalytic synthesis of benzoxazoles in a process that has high functional group tolerance. The presence of a directing group at the meta position markedly improves the reaction efficacy and a variety of 7-substituted benzoxazoles are selectively produced under mild reaction conditions. The mechanism of the reaction is also discussed in this report.
Ueda
Satoshi
S
Laboratory of Medicinal and Pharmaceutical Chemistry, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585, Japan.
Nagasawa
Hideko
H
D000388:Air; D001583:Benzoxazoles / Q000138:chemical synthesis*; D002384:Catalysis; D003300:Copper; D010100:Oxygen / Q000737:chemistry
D001583:Benzoxazoles; D003300:Copper; D010100:Oxygen