Copper(II)-Catalyzed Conversion of Bisaryloxime Ethers to 2-Arylbenzoxazoles via C−H Functionalization/C−N/C−O Bonds Formation
摘要:
A copper(II)-catalyzed conversion of bisaryloxime ethers to 2-arylbenzoxazoles has been developed. The reaction involves a cascade C H functionalization and C N/C-O bond formation under oxygen atmosphere.
Copper-Mediated Synthesis of Substituted 2-Aryl-N-benzylbenzimidazoles and 2-Arylbenzoxazoles via C–H Functionalization/C–N/C–O Bond Formation
摘要:
An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
A novel method for the synthesis of O-aryloxime is described. It consisted of the coupling reaction between phenylboronic acids and aryloximes in the presence of catalytic quantities of copper(II) acetate. This reaction takes place in the presence of pyridine under a mild condition (DCE, Rt, 24-36h) with moderate yield. It represents a good alternative to known methods for O-aryloxime synthesis.