The monoallylation of aniline to give N-allyl aniline is a fundamental transformation process that results in various kinds of valuable building block allyl compounds, which can be used in the production of pharmaceuticals and electronic materials. For decades, sustainable syntheses have been gaining much attention, and the employment of allyl alcohol as an allyl source can follow the sustainability due to the formation of only water as a coproduct through dehydrative monoallylation. Although the use of homogeneous metal complex catalysts is a straightforward choice for the acceleration of dehydrative monoallylation, the use of soluble catalysts tends to contaminate products. We herein present a 10 wt% WO₃/ZrO₂ catalyzed monoallylation process of aniline to give N-allyl anilines in good yields with excellent selectivity, which enables the continuous selective flow syntheses of N-allyl aniline with 97–99% selectivity. The performed detailed study about the catalytic mechanism suggests that the dispersed WO₃ with the preservation of the W(VI) oxidation state of 10 wt% WO₃/ZrO₂ with appropriate acidity and basicity is crucial for the monoallylation. The inhibition of the over allylation of the N-allyl anilines is explained by the unwilling contact of the N-allyl aniline with the active sites of WO₃/ZrO₂ due to the steric hindrance.

中文翻译：

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使用可重复使用的二氧化锆负载氧化钨固体催化剂将苯胺选择性单烯丙基化为 N-烯丙基苯胺

苯胺单烯丙基化生成N-烯丙基苯胺是一个基本的转化过程，可产生各种有价值的结构单元烯丙基化合物，可用于制药和电子材料的生产。几十年来，可持续合成受到了广泛关注，并且使用烯丙醇作为烯丙基来源可以遵循可持续性，因为通过脱水单烯丙基化仅形成水作为副产物。尽管使用均相金属络合物催化剂是加速脱水单烯丙基化的直接选择，但使用可溶性催化剂往往会污染产品。我们在此提出了 10 wt% WO ₃ /ZrO ₂催化苯胺单烯丙基化过程以良好的收率和优异的选择性得到N-烯丙基苯胺，这使得N-烯丙基苯胺的连续选择性流动合成具有 97-99% 的选择性。对催化机理进行的详细研究表明，分散的WO _{3保持10 wt% WO 3} /ZrO ₂的W( VI )氧化态并具有适当的酸度和碱度对于单烯丙基化反应至关重要。N-烯丙基苯胺过度烯丙基化的抑制可以通过N-烯丙基苯胺与 WO ₃ /ZrO的活性位点的非自愿接触来解释₂由于空间位阻。