Sumii Yuji, Sugita Yutaka, Tokunaga Etsuko, Shibata Norio
Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan.
Institute of Advanced Fluorine-Containing Materials Zhejiang Normal University 688 Yingbin Avenue 321004 Jinhua China.
ChemistryOpen. 2018 Feb 27;7(2):204-211. doi: 10.1002/open.201700204. eCollection 2018 Feb.
The direct synthesis of aryl triflones, that is, trifluoromethanesulfonyl arenes, was achieved through the trifluoromethanesulfonylation of benzynes. The trifluoromethanesulfonyl group, one of the fluorinated functional groups, is a highly electron-negative and mild lipophilic substituent. Aryl triflones have high potential in the synthesis of bioactive compounds and specialty materials. The treatment of 2-(trimethylsilyl)aryl trifluoromethanesulfonates with cesium fluoride in the presence of 15-crown-5 generated benzynes, which reacted with sodium trifluoromethanesulfinate followed by protonation with BuOH under heating conditions, provided aryl triflones in moderated to good yields. Both symmetrical and unsymmetrical triflones were nicely accessed under the same reaction conditions. Interestingly, the trifluoromethanesulfonylation of unsymmetrical benzyne precursors proceeded smoothly to furnish corresponding aryl triflones in good yields with good to high regioselectivities. The balance of polarization of electric charge as well as steric hindrance of the benzyne intermediates are central factors to control the outcome of regioselectivity.
通过苯炔的三氟甲磺酰化反应实现了芳基三氟甲磺酸盐（即三氟甲磺酰基芳烃）的直接合成。三氟甲磺酰基作为氟化官能团之一，是一种高度电负性且亲脂性适中的取代基。芳基三氟甲磺酸盐在生物活性化合物和特种材料的合成中具有很高的潜力。在15-冠-5存在下，用氟化铯处理2-（三甲基甲硅烷基）芳基三氟甲磺酸盐生成苯炔，苯炔与三氟甲亚磺酸钠反应，然后在加热条件下用丁醇质子化，以中等至良好的产率得到芳基三氟甲磺酸盐。在相同的反应条件下，对称和不对称的三氟甲磺酸盐都能顺利得到。有趣的是，不对称苯炔前体的三氟甲磺酰化反应顺利进行，以良好的产率和良好至高的区域选择性提供相应的芳基三氟甲磺酸盐。苯炔中间体的电荷极化平衡以及空间位阻是控制区域选择性结果的核心因素。
