Nucleophilic Addition to Nitrones Using a Flow Microreactor

Nucleophilic addition reactions of soft carbon nucleophiles to nitrones in a flow microreactor are reported for the first time. Under microflow conditions at 30 °C to 0 °C, a range of nitrones can be efficiently transformed into the corresponding oxyiminium ions by reacting with either acyl halides or trialkylsilyl triflates, which can subsequently undergo the addition of nucleophiles including allyltributylstannane, ketene methyl tert-butyldimethylsilyl acetal, and N-silyl ketene imines to afford the corresponding adducts in high yields, while such reactions at a similar temperature under batch conditions have resulted in lowering the yields due to undesired side reactions.