An Effective Method for Acylation of Weakly Nucleophilic Anilines with Silyl Carboxylates via Mixed Anhydrides
作者:Mitsutomo Miyashita、Isamu Shiina、Teruaki Mukaiyama
DOI:10.1246/bcsj.67.210
日期:1994.1
In the presence of a catalytic amount of active titanium(IV) salt generated in situ from 1 mol of TiCl4 and 2 mol of AgOTf, weakly nucleophilic anilines react under mild conditions with nearly equimolar amounts of silyl carboxylates to afford the corresponding anilides in excellent yields using 4-(trifluoromethyl)benzoic anhydride. The mixed anhydride formed in situ from trimethylsily acetate and 4-(trifluoxomethyl)benzoic anhydride, a key intermediate of this reaction, was detected by 1H NMR experiment. Further, it was shown that the reaction of the mixed anhydrides and 2-nitroaniline was faster than that of the corresponding homo anhydrides and 2-nitroaniline.
在由1摩尔TiCl4和2摩尔AgOTf原位生成的催化量活性钛(IV)盐存在下,弱亲核性苯胺在温和条件下与几乎等摩尔量的硅基羧酸盐反应,使用4-(三氟甲基)苯甲酸酐,以优异的产率得到相应的苯胺酰胺。通过1H NMR实验检测到由三甲基硅基乙酸酯和4-(三氟甲氧基)苯甲酸酐原位形成的混合酐,这是该反应的关键中间体。进一步表明,混合酐与2-硝基苯胺的反应速率比相应的同系酐与2-硝基苯胺的反应速率更快。