The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives

Shunsuke Kuribayashi; Tomoyuki Kurioka; Shinsuke Inagi; Ho-Jung Lu; Biing-Jiun Uang; Toshio Fuchigami

doi:10.3762/bjoc.14.27

The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives

Beilstein J Org Chem. 2018 Feb 12:14:389-396. doi: 10.3762/bjoc.14.27. eCollection 2018.

Authors

Shunsuke Kuribayashi¹, Tomoyuki Kurioka², Shinsuke Inagi², Ho-Jung Lu³, Biing-Jiun Uang³, Toshio Fuchigami¹

Affiliations

¹ Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan.
² Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan.
³ Department of Chemistry, National Tsing Hua University, 101, Sec 2, Kuang Fu Rd., Hsinchu 300, Taiwan, R.O.C.

Abstract

We herein report that the regioselective anodic fluorination of S-alkyl benzothioate and its derivatives in various aprotic solvents using Et₃N·nHF (n = 3-5) and Et₄NF·nHF (n = 3-5) as supporting electrolyte and a fluorine source successfully provided the corresponding α-fluorinated products in moderate yields. Dichloromethane containing Et₄NF·4HF was found to be the most suitable combination as electrolytic solvent and supporting salt as well as fluorine source for the anodic fluorination. The electrochemical fluorination of cyclic benzothioates such as benzothiophenone was also achieved.

Keywords: anodic cyclization; diastereoselective fluorination; electrosynthesis; fluorobenzothiophenone; selective fluorination.