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.