Background: A novel one-pot N-heterocyclic carbene (NHC)-catalysed acylation of 2- bromoacetonitrile with aromatic aldehydes is reported. The protocol involves carbonyl umpolung reactivity of aldehydes in which the carbonyl carbon attacks nucleophilically (as d1 nucleophile) on the electrophilic terminal of 2-bromoacetonitrile to afford 3-aryl-3-oxopropanenitrile. The salient features of this procedure are short reaction time, operational simplicity, ambient temperature, no by-product formation and high yields.

Materials and Methods: A flame-dried round bottom flask was charged with Imidazolium salts (3a) (0.20 mmol). Aldehyde 1a (1.0 mmol), 2-bromoacetonitrile 2 (1.0 mmol), and THF / t-BuOH 5 mL; 10:1) were added at positive nitrogen pressure followed by the addition of DBU (0.15 mmol) through stirring. The resulting yellow- orange solution was stirred at room temperature for 5-6 h. After completion of the reaction (TLC monitored), the reaction mixture was concentrated under reduced pressure. The product was purified using hexane / EtOAc (10:1) as an eluent to provide analytically pure compound 4a. Physical data of representative compounds and the NMR spectroscopic data are in agreement with the literature value.

Results and Discussion: The salient features of this procedure are short reaction time, operational simplicity, ambient temperature, no by-product formation and high yields.

Conclusion: To sum up, we have developed a convenient, efficient and one-pot route for 3-oxo-3- phenylpropanenitrile synthesis from NHC promoted direct nucleophilic acylation of aromatic aldehydes using 2- bromoacetonitrile. This method provided a wide range of products and good yields. To best of our knowledge, this is the new report for the synthesis of 3-oxo-3-phenylpropanenitrile through NHC promoted nucleophilic acylation of aromatic aldehyde.

背景：报道了一种新型的一锅N-杂环卡宾（NHC）催化的2-溴乙腈与芳族醛的酰化反应。该规程涉及醛的羰基氨酚反应性，其中羰基碳亲核（如d1亲核体）攻击2-溴乙腈的亲电子端，得到3-芳基-3-氧代丙烷腈。该方法的显着特征是反应时间短，操作简便，环境温度高，无副产物形成和产率高。

材料和方法：在火焰干燥的圆底烧瓶中装入咪唑鎓盐（3a）（0.20 mmol）。醛1a（1.0 mmol），2-溴乙腈2（1.0 mmol）和THF / t-BuOH 5 mL; 在正氮气压力下加入10∶1），然后通过搅拌加入DBU（0.15mmol）。将所得的黄橙色溶液在室温下搅拌5-6小时。反应完成后（监控TLC），将反应混合物减压浓缩。使用己烷/ EtOAc（10：1）作为洗脱剂纯化产物，以提供分析纯的化合物4a。代表性化合物的物理数据和NMR光谱数据与文献值一致。

结果与讨论：该方法的主要特点是反应时间短，操作简便，环境温度高，无副产物形成和高收率。

结论：综上所述，我们已经开发了一种便捷，有效且一锅法的方法，该方法可通过NHC促进2-氧代乙腈对芳香族醛的直接亲核酰化反应来合成3-氧代-3-苯基丙腈。该方法提供了广泛的产品和良好的产率。据我们所知，这是通过NHC促进芳族醛的亲核酰化反应合成3-氧代-3-苯基丙腈的新报告。