Copper-catalyzed oxidative trifluoromethylthiolation of aryl boronic acids with TMSCF3 and elemental sulfur.

Content Provider	Semantic Scholar
Author	Chen, Chao Xie, Yan Chu, Lingling Wang, Ruowen Zhang, Xingang Qing, Feng-Ling
Copyright Year	2012
Abstract	Fluorinated functional groups are key structural units found in various pharmaceuticals and agrochemicals. Approximately 30 % of all agrochemicals and 20% of all pharmaceuticals on the market contain fluorine. Among these substituents, the trifluoromethylthio group (CF3S ), especially as an aromatic substituent, plays an important role because of its strong electron-withdrawing effect and high lipophilicity. These characteristics are similar to those of trifluoromethyl (CF3 ) and trifluoromethoxy (CF3O ) groups. Additionally, aryl trifluoromethyl thioethers (CF3SAr) are also key intermediates in the preparation of trifluoromethyl sulfoxide and sulfone, which are important trifluoromethylation reagents. Although impressive progress has been made in the trifluoromethylation of arenes in the past several years, only a few methods are available for the synthesis of aryl trifluoromethyl thioethers. Generally, aryl trifluoromethyl thioethers are prepared either by a nucleophilic reaction of trifluoromethylthiolate with aryl halides, or by a nucleophilic or radical reaction of aryl sulfides and disulfides with a trifluoromethylation reagent. However, these methods are variously limited by a combination of high temperatures, expensive reagents, and low reactivity with electron-rich aromatic groups. Thus, the development of general, safe, and efficient methods to access aryl trifluoromethyl thioethers is highly desirable. Very recently, Buchwald reported a palladium-catalyzed trifluoromethylthiolation of aryl bromides with CF3SAg. [10] This breakthrough for the preparation of ArSCF3 is highly efficient and compatible with a variety of functional groups. However, from the point view of cost-effectiveness and synthetic convenience, using readily available and inexpensive catalysts and fluorinated reagents, such as copper and (trifluoromethyl)trimethylsilane (the Ruppert–Prakash reagent, TMSCF3), to access aryl trifluoromethyl thioethers would be an attractive alternative. The present study was inspired by our own and Buchwald s recent investigations into the copper mediated oxidative trifluoromethylation of arylboronic acid with TMSCF3, [11] as well as Karlin s observation of the formation of a stable copper disulfide complex from the reaction of elemental sulfur (S8) with a Cu I complex. We hypothesized that a Cu disulfide complex generated in situ (II ; Scheme 1) would
Starting Page	101
Ending Page	107
Page Count	7
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://lac.dicp.ac.cn/tswz/mc-9.pdf
PubMed reference number	22287539v1
Alternate Webpage(s)	https://doi.org/10.1002/anie.201108663
DOI	10.1002/anie.201108663
Journal	Angewandte Chemie
Volume Number	51
Issue Number	10
Language	English
Access Restriction	Open
Subject Keyword	AROMATICS Agrochemicals Amino Acids, Branched-Chain Aryl Hydrocarbon Hydroxylases Boronic Acids Bromides Carbon Disulfide Copper Dimethyl Sulfoxide Disulfides Dosage Forms Fluorine Inspiration function Palladium Reagents Sulfides Sulfones Sulfoxides Thioctic Acid Thioethers arylsulfatase activity trimethyl(trifluoromethyl)silane
Content Type	Text
Resource Type	Article