Copper‐Catalyzed Direct C−H Bond Arylation of Benzoxazoles with Anilines

Abstract

An efficient and easily managed protocol was developed for the synthesis of 2-aryl-substituted benzoxazoles by using ac opper-catalyzed CÀHa rylation reactionb etween benzoxazole derivatives and in situ generated aryl diazonium salts. Under the optimized conditions, aw ide variety of products were selectively obtained in moderate to good yields. Diphenylamine and 2,3'-bipyridine were also obtained under the same reaction conditions by employing aniline and pyridin-3-amine, respectively,a st he sole startingm aterial.[a] Dr.

Metal-Free Transformation of Sulfonyl Oxime Ethers with Amines to Oxime Ethers

“…According to the above investigations and the literature, a proposed mechanism involving the radical process is depicted in Scheme for the arylation of phenylsulfonyl oxime ethers. Initially, the aniline 1 reacts with t BuONO to yield the aryl diazonium salt I . Subsequently, the diazonium salt I is protonated by ascorbic acid and leads to diazonium salt II .…”

Copper‐Catalyzed Electrophilic Amination of Benzoxazoles via Magnesation

“…All work‐up and purification procedures were carried out with reagent grade solvents in air. A variety of oxazole derivatives and O ‐benzoyl hydroxylamine were prepared according to reported experimental procedures.…”

Recent Advances in Copper(II)-Mediated or -Catalyzed C–H Functionalization

“…Wang and co-workers developed an efficient and easily manipulated reaction protocol for the copper-mediated direct C-H bond arylation of benzoxazoles with anilines (Scheme 20). 23 The actual arylation reagent was the arenediazonium generated in situ from inexpensive and readily available anilines. Some functional groups, such as chloride, bromide, iodide, trifluoromethyl, and ester were well tolerated under the heating conditions.…”