d, l-allal- and - d, l-galactal-derived vinyl N-nosyl aziridines as useful tools for the synthesis of 4-deoxy-4-( N-nosylamino)-2,3-unsaturated-5 a-carbasugars]]>

摘要

AbstractThe novel carba-d,l-allal- and carba-d,l-galactal-derived vinylN-nosyl aziridines were prepared and the regio- and stereoselective behavior in opening reactions withO- andN-nucleophiles examined. The carbaglycosylating ability of the novel aziridines, as deduced by the amount of1,4-addition products(1,4-regioselectivity) obtained in the acid-catalyzed methanolysis taken as a model reaction, is similar or superior to that observed with the corresponding carba-d,l-allal- and -d,l-galactal-derived vinyl epoxides, respectively. In all1,2-and1,4-addition productsobtained, a –(N-nosylamino) group is regio- and stereoselectively introduced at the C(4) carbon of a 1,2- or 2,3-unsaturated carbasugar, susceptible to further elaborations toward aminocyclitol derivatives. The stereoselective synthesis of the corresponding, enantiomerically pure carba-d,l-allal- and -d,l-galactal-derived vinylN-acetyl aziridines is also described.展开▼