Direct Arylation of Benzoxazoles with Benzoyl Chlorides under Mild Conditions

A mild and convenient method for the arylation of benzoxazoles with benzoyl chlorides is reported. This facile protocol used only N,N‐diisopropylethylamine (DIPEA) as an additive. Under the optimal reaction conditions, a wide range of benzoxazoles and benzoyl chlorides were tolerated. With this strategy, benzothiazoles and benzoyl chlorides also reacted well to afford the desired product 2‐aryl benzothiazoles in moderate yields. A practical strategy for the direct arylation of benzoxazoles is described. By treating benzoxazoles with benzoyl chlorides in the presence of DIPEA in DCM/H2O, the corresponding 2‐aryl benzoxazoles were obtained. This procedure was carried out without transition‐metal catalysts or extra oxidants. Notably, the same transformation can also be effected with benzothiazoles.