title: S8 -Mediated Cyclization of 2-Aminophenols/thiophenols with Arylmethyl Chloride: Approach to Benzoxazoles and Benzothiazoles.
abstract: A metal-free approach to benzazoles from arylmethyl chlorides and 2-mercaptan/2-hydroxyanilines using elemental sulfur as a traceless oxidizing agent has been developed. The reactions proceeded in good to excellent yields, exhibiting good functional groups tolerance and gram-scale ability. A key mechanistic investigation indicated that the key intermediate trisulfide 6, which was characterized by NMR, HRMS and crystal X-ray crystallography, was separated in the reaction prior to the formation of the product.
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Gan
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China.
authors.forename: Dazhuang
authors.initials: D
authors.lastname: Miao
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Pan
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China.
authors.forename: Renhe
authors.initials: R
authors.lastname: Hu
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, P. R. China. hanshiqing@njtech.edu.cn.|Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, CAS, Shanghai, 200032, P. R. China. hanshiqing@njtech.edu.cn.
authors.forename: Shiqing
authors.initials: S
authors.lastname: Han
keywords: arylmethyl chlorides; benzothiazoles; benzoxazoles; cyclization; sulfur