Water Microdroplet Chemistry for Accelerating Green Thiocyanation and Discovering Water-Controlled Divergence
Water Microdroplet Chemistry for Accelerating Green Thiocyanation and Discovering Water-Controlled Divergence
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DOI：
10.1021/acssuschemeng.3c03313
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发表时间：
2023-08
期刊：
影响因子：
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通讯作者：
Luyun Xue;Boyu Zheng;Jiannan Sun;Jinhua Liu;Heyong Cheng
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文献类型：
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作者：
Luyun Xue;Boyu Zheng;Jiannan Sun;Jinhua Liu;Heyong Cheng
吡唑啉-5- 1衍生物是一类重要的五元n杂环化合物，在精细化学品和生物活性分子的构建中发挥着极其重要的作用。传统的功能化合成方法（如硫氰化）采用有机溶剂，反应缓慢，存在环境污染、效率低、成本高等问题。在此，我们开发了一种绿色、高效、克级的吡唑啉酮硫氰化方法。使用水作为溶剂，这种微滴法减少了氧化剂的当量，并在几毫秒内完成硫氰化反应（收率为90%）（单个微滴的反应时间，尽管实际可检测产品的收集时间在几分钟到几小时之间）。水微滴法适用于各种吡唑啉酮衍生物，其反应收率远高于本体反应。此外，我们通过水微滴化学有效地发现了水在驱动不同反应途径中的独特作用。在有水存在的情况下，吡唑啉酮与硫氰酸铵孵育产生串联硫氰化/铵交叉偶联产物，而纯有机溶剂中只有硫氰化产物，导致可能的水控发散。
As an important class of five-memberedN-heterocyclic compounds, pyrazolin-5-one derivatives play an extremely important role in the construction of fine chemicals and bioactive molecules. Traditional synthetic methods for functionalization (i.e., thiocyanation) used organic solvents to undergo slow reactions, which poses problems such as environmental pollution, low efficiency, and high cost. Herein, we develop a green, efficient, and gram-scale pyrazolinone thiocyanation method by water microdroplet chemistry. Using water as the solvent, this microdroplet method reduced the equivalent of oxidant and completed the thiocyanation reaction (>90% yields) within milliseconds (reaction time for a single microdroplet, although the actual collection time for detectable amounts of products is on the order of minutes to hours). The water microdroplet method was suitable for various pyrazolinone derivatives, and the yields of the aqueous microdroplet reactions were much higher than those of bulk reactions. In addition, we efficiently discovered a unique role of water in driving different reaction pathways by aqueous microdroplet chemistry. In the presence of water, pyrazolinone incubated with ammonium thiocyanate afforded tandem thiocyanation/ammonium cross-coupling products, compared to only thiocyanated products in pure organic solvents, leading to a possible water-controlled divergence.