Synthesis 2018; 50(15): 2948-2953
DOI: 10.1055/s-0037-1609759
special topic
© Georg Thieme Verlag Stuttgart · New York

Simple Photo-Induced Trifluoromethylation of Aromatic Rings

Hiromichi Egami*
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan   Email: hamashima@u-shizuoka-ken.ac.jp   Email: hegami@u-shizuoka-ken.ac.jp
,
Yuta Ito
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan   Email: hamashima@u-shizuoka-ken.ac.jp   Email: hegami@u-shizuoka-ken.ac.jp
,
Takafumi Ide
,
Shuya Masuda
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan   Email: hamashima@u-shizuoka-ken.ac.jp   Email: hegami@u-shizuoka-ken.ac.jp
,
Yoshitaka Hamashima*
School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan   Email: hamashima@u-shizuoka-ken.ac.jp   Email: hegami@u-shizuoka-ken.ac.jp
› Author Affiliations
This work was supported by a Grant-in-Aid for Scientific Research (B) (No. 16H05077) from JSPS, and a grant under Basis for Supporting Innovative Drug Discovering and Life Science Research (BINDS) from AMED.
Further Information

Publication History

Received: 28 March 2018

Accepted after revision: 23 April 2018

Publication Date:
26 June 2018 (eFirst)

Published as part of the Special Topic Modern Radical Methods and their Strategic Applications in Synthesis

Abstract

The trifluoromethylation of various aromatic compounds with Umemoto reagent II (2,8-difluoro-5-(trifluoromethyl)-5H-dibenzo[b,d]thiophen-5-ium triflate) proceeded in moderate to good yields under simple photo-irradiation conditions without any catalyst, additive, or activator. UV-Vis and NMR spectral analyses indicated that pre-formation of an electron donor-acceptor complex between the trifluoromethylating reagent and the substrate, as proposed in previous studies, is not essential for generation of the trifluoromethyl radical. Instead, the radical appears to be formed by simple photo-activation of the Umemoto reagent.

Supporting Information

 
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