Synthèse de “sulfahydatoïnes” chirales. Aspects stéréochimiques et protection régiospécifique.
摘要:
The enantiospecific synthesis of N2-benzyl-1-thia-2,5-diazolidin-3-one dioxides (sulfa-analogues of hydantoins) was carried out through two convergent pathways starting from chlorosulfonyl isocyanate (CSI) and chiral alpha amino- and hydroxyesters. The intermediate carboxylsulfamides (containing ''activated sulfamoyl group'') react easily in the Mitsunobu conditions to give ultimately the N-protected sulfa-hydantoins, or symmetric and dissymmetric sulfones of bis-N-aminoesters. The non-racemization during the cyclization of N-sulfamylaminoesters in alkaline conditions was established by chemical and spectroscopic methods (nmr with chiral Eu(hfc)3).
We developed one-flow syntheses of unsymmetrical sulfamides and N-substituted sulfamate esters by changing a nucleophile and a tertiary amine from inexpensive and commercially available chlorosulfonic acid. In the synthesis of N-substituted sulfamate esters, unexpected symmetrical sulfite formation was suppressed by changing the tertiary amine. The effect of tertiary amines was proposed using linear