Highly Efficient Michael Reactions of Nitroolefins by Grinding Means.

AIM AND OBJECTIVE: The direct ß-functionalization of trans-ß-nitroolefins by Michael reaction is regarded as an efficient way to provide precursors for ß-functional amines. However, Michael additions by grinding means with solvent-free conditons are rarely reported. We have developed facile access to ß-functional nitroalkanes by grinding means under solvent-free conditions. MATERIALS AND METHODS: From commercially available materials including ethyl 2-nitroacetate, alkyl 2-cyanoacetates and malononitrile, the grinding reactions between these above-mentioned activated methylenecompounds and various trans-ß-nitroolefins were performed at room temperature and solvent-free conditions. RESULTS: A highly efficient direct Michael reaction of nitroolefins by simple grinding means has been developed. Various trans-nitrostyrenes were easily converted into corresponding ß-functional nitroalkanes in excellent yields within 5~10 min (up to 36 examples). CONCLUSION: Herein, we have developed a simple and efficient way to ß-functional nitroalkanes through Michael reactions by grinding means. The grinding Michael reaction is fast, clean and stable and these Michael adducts could be easily converted into the other amino compounds served as building blocks in organic synthesis.