Triple Mode of Alkylation with Ethyl Bromodifluoroacetate:
<i>N</i>
, or
<i>O</i>
‐Difluoromethylation,
<i>N</i>
‐Ethylation and
<i>S</i>
‐(ethoxycarbonyl)difluoromethylation
作者:Arghya Polley、Gurupada Bairy、Pritha Das、Ranjan Jana
DOI:10.1002/adsc.201800824
日期:2018.11.5
chemical reactivity of ethylbromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethylbromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoteddifluoromethylation of tosyl‐protected aniline
在这份报告中,我们探索了溴二氟乙酸乙酯的化学反应的三重模式。通常,溴二氟乙酸已被用作软亲核试剂的二氟甲基化的二氟卡宾前体。在这里,我们已经公开了溴二氟乙酸乙酯的亲核性和碱依赖性发散化学反应性。它提供了氢氧化锂和碳酸铯,分别促进了甲苯磺酰基保护的苯胺和缺电子的酚的二氟甲基化作用。有趣的是,将碱从氢氧化锂转变为4- N,N-二甲基氨基吡啶(DMAP)甲苯磺酰基保护的苯胺,得到了相应的N-乙基化产物。而高度亲核的苯硫酚提供了相应的S羰基乙氧基二氟甲基化产物在酯水解之前通过快速的S N 2攻击溴原子而形成。这种机制差异是通过几个控制实验确定的。结果表明,二氟甲基化反应是通过串联原位酯水解/脱羧-脱溴化二氟卡宾的形成并随后被软亲核试剂-NHTs或电子缺陷型酚-OH基团捕获而进行的。在DMAP的存在下,酯的水解受到干扰,相反,在乙基部分的亲核攻击提供了N-乙基化产物。因此,除了开发实用的碱促氮素胺和电
Electrophilic (Ethoxycarbonyl)difluoromethylthiolation Using Difluoroalkyl Sulfonium Salts
We report a simple protocol for (ethoxycarbonyl)difluoromethylthiolation of nucleophilic compounds using a difluoroalkyl sulfonium salt which can be prepared in situ via Tf2O-triggered electrophilic activation of a benzyl difluoroalkyl sulfoxide. With the protocol, difluoroalkylthiolated arenes, heteroarenes, α-difluoroalkylthiolated carbonyl compounds, etc. were obtained smoothly with good to excellent
我们报告了一种使用二氟烷基锍盐对亲核化合物进行(乙氧基羰基)二氟甲基硫醇化的简单方案,该盐可以通过 Tf 2 O 触发的苄基二氟烷基亚砜的亲电活化原位制备。通过该协议, 顺利获得了二氟烷基硫醇化芳烃、杂芳烃、α-二氟烷基硫醇化羰基化合物等, 收率良好。该反应的优点包括容易获得的二氟烷基硫醇化试剂和底物、温和的条件和出色的区域选择性。
<i>N</i>-Difluoromethylthiophthalimide Reagents for Modular Synthesis of Diversified α-Difluoromethylthiolated Ketones
N-difluoromethylthiophthalimide reagents that can be easily prepared with commercially available and economical chemicals. These reagents could smoothly react with various nucleophiles, such as Grignardreagents, boronic acids, β-keto esters, and anilines, which affords structurally diverse α-difluoromethylthiolated ketones in good to excellent yields. The formal synthesis of active antifungal compounds positively