A mechanochemical approach to access the proline–proline diketopiperazine framework
نویسندگان
چکیده
Ball milling was exploited to prepare a substituted proline building block by mechanochemical nucleophilic substitution. Subsequently, the mechanocoupling of hindered proline amino acid derivatives was developed to provide proline-proline dipeptides under solvent-free conditions. A deprotection-cyclization sequence yielded the corresponding diketopiperazines that were obtained with a high stereoselectivity which could be explained by DFT calculations. Using this method, an enantiopure disubstituted Pro-Pro diketopiperazine was synthesized in 4 steps, making 5 new bonds using a ball mill.
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