Benzylic C-H Trifluoromethylation via Photoenol
Benzylic C-H Trifluoromethylation via Photoenol
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DOI：
10.1021/acs.orglett.7b01971
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发表时间：
2017-09-01
期刊：
影响因子：
5.2
通讯作者：
Hamashima, Yoshitaka
中科院分区：
文献类型：
--
作者：
Ide, Takafumi;Masuda, Shuya;Hamashima, Yoshitaka
由邻甲基取代的苯基酮（例如二苯甲酮和苯乙酮）原位生成的光烯醇，用 Togni 试剂进行三氟甲基化，无需任何添加剂或催化剂。该三氟甲基化反应在光照射条件（365 nm）下顺利进行。各种官能团都能耐受反应条件。有趣的是，三氟甲基仅在邻苄基位置引入。机理研究表明，该反应是通过形成光烯醇而不是通过自由基途径进行的。
Photoenols generated in situ from ortho-methyl-substituted phenylketones such as benzophenones and acetophenones were trifluoromethylated with Togni reagent without any additive or catalyst. This trifluoromethylation reaction proceeded smoothly under photoirradiation conditions (365 nm). Various functional groups were tolerant of the reaction conditions. Interestingly, the trifluoromethyl group was exclusively introduced at the ortho-benzylic position. Mechanistic studies suggested that this reaction proceeds via formation of a photoenol, not via a radical pathway.