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Cyclodipepflde (3S, 6S )-bis (phenylmethyl) piperazlne-2,5-dione was prelmred in high yield by heating phenylalanine methyl ester in toluene under reflux. The reduction of this cydodipeptide with sodium NaBH4-BF3 in DIME gave the (2S ,SS)-bis(phenyl-methyl)plperazine, which, on heating with ethylene bromide and triethyiamine, afforded the title compounds. This methodwas proved to be generally applicable to the synthesis of C2-symmetric 2, 5-disubsiituted=l, 4-diazabicyclo [ 2.2.2 ] octanefrom the corresponding natural or unnatural amino acid esters. 相似文献
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从脯氨酸合成一种三齿手性配体及其在二乙基锌对醛的对映选择性加成中的应用 总被引:1,自引:0,他引:1
A new chiral tridentate ligand [1-(1-methyl-S-pyrrolidin-2-ylmethyl)-S-pyrrolidin-2-yl]-diphenylmethanol (1) has been successfully synthesized from S-proline. The structure of the ligand was characterized by NMR spectra and X-ray diffraction analysis. Its catalytic ability has also been examined in enantioselective addition of diethylzinc towards aldehydes with 15%-84% enantiomeric excesses (ee). 相似文献
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Introduction1,4 Diazabicyclo[2 .2 .2 ]octane (DABCO)wasre portedtocatalyzeorganicreactionsduetoitsstrongbasici ty .1,2 Severalchiraltrans 2 ,3 disubstitutedDABCOshavebeensynthesizedandappliedtotheasymmetricBaylis Hillmanreaction3andvicinalhydroxylation .4ThefirstsynthesisofthetitlecompoundwasreportedbySoai5from (2S ,5S) bis(phenylmethyl)piperazine (1) ,asshowninScheme 1.Butthisprocedureislengthy ,andtheoverallyieldisnotsosatisfactory .Besides ,thereport edmethodforthepreparationof 1is… 相似文献
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