Stereoselective synthesis of (R)- and (S)-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxylic acids, -carboxylates and -carboxamides
                                
                                    
                                        作者:Matej Breznik、Valentina Hrast、Alenka Mrcina、Danijel Kikelj                                    
                                    
                                        DOI:10.1016/s0957-4166(98)00485-6
                                    
                                    
                                        日期:1999.1
                                    
                                    (R)-Monomethyl 2-methyl-2-(2- nitrophenoxy)malonates obtained by PLE catalyzed hydrolysis of the corresponding dimethyl malonates undergo solvent-dependent enantioselective cyclization to afford (R)-methyl 2-methyl-3-oxo-3,4-dihydro-2H-1,4-hentoxazine-2-carboxylates and (S)-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-2-carboxyIic acids, respectively. These compounds are easily converted to enantiomerically and diastereomerically pure carboxamides, which are used as peptidomimetic building blocks. (C) 1999 Elsevier Science Ltd. All rights reserved.