The diastereoselective electrochemical carboxylation of chiral N-(2-bromoacyl)oxazolidin-2-ones has been studied. This reaction was carried out by cathodic reduction of the C-Br bond, in the presence of carbon dioxide, followed by treatment with diazomethane. The yields and the diastereomeric ratio of the two epimeric alkylmalonic acid derivatives are strongly affected by various factors: solvent-supporting electrolyte system, temperature, electrode material, electrolysis conditions, oxazolidinone moiety. The higher yields (88%) were obtained starting from N-(2-bromopropionyl)4R-phenyloxazolidin-2-one la, but with poor diastereoselectivity (61:39). The two epimers were easily separated by flash chromatography. The best results were achieved using a different chiral auxiliary: Oppolzer's camphor sultam. Starting from 1j a good yield in carboxylated product was obtained (80%) with excellent diastereoselectivity (98:2). These chiral alkylmalonic acid derivatives are valuable building blocks in the synthesis of molecules with biological activity and of chiral propane-1,3-diols derivatives.
FEROCI M., ORSINI M., PALOMBI L., SOTGIU G, COLAPIETRO M., & INESI A. (2004). Diastereoselective electrochemical carboxylation of chiral ?-bromocarboxylic acid derivatives: an easy access to unsymmetrical alkylmalonic ester derivatives. JOURNAL OF ORGANIC CHEMISTRY, 69(2), 487-494.
Titolo: | Diastereoselective electrochemical carboxylation of chiral ?-bromocarboxylic acid derivatives: an easy access to unsymmetrical alkylmalonic ester derivatives |
Autori: | |
Data di pubblicazione: | 2004 |
Rivista: | |
Citazione: | FEROCI M., ORSINI M., PALOMBI L., SOTGIU G, COLAPIETRO M., & INESI A. (2004). Diastereoselective electrochemical carboxylation of chiral ?-bromocarboxylic acid derivatives: an easy access to unsymmetrical alkylmalonic ester derivatives. JOURNAL OF ORGANIC CHEMISTRY, 69(2), 487-494. |
Abstract: | The diastereoselective electrochemical carboxylation of chiral N-(2-bromoacyl)oxazolidin-2-ones has been studied. This reaction was carried out by cathodic reduction of the C-Br bond, in the presence of carbon dioxide, followed by treatment with diazomethane. The yields and the diastereomeric ratio of the two epimeric alkylmalonic acid derivatives are strongly affected by various factors: solvent-supporting electrolyte system, temperature, electrode material, electrolysis conditions, oxazolidinone moiety. The higher yields (88%) were obtained starting from N-(2-bromopropionyl)4R-phenyloxazolidin-2-one la, but with poor diastereoselectivity (61:39). The two epimers were easily separated by flash chromatography. The best results were achieved using a different chiral auxiliary: Oppolzer's camphor sultam. Starting from 1j a good yield in carboxylated product was obtained (80%) with excellent diastereoselectivity (98:2). These chiral alkylmalonic acid derivatives are valuable building blocks in the synthesis of molecules with biological activity and of chiral propane-1,3-diols derivatives. |
Handle: | http://hdl.handle.net/11590/143311 |
Appare nelle tipologie: | 1.1 Articolo in rivista |