Carba-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-5a-carbasugars

Abstract The novel carba- d , l -allal- and carba- d , l -galactal-derived vinyl N -nosyl aziridines were prepared and the regio- and stereoselective behavior in opening reactions with O - and N -nucleophiles examined. The carbaglycosylating ability of the novel aziridines, as deduced by the amount of 1,4-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 all 1,2- and 1,4-addition products obtained, 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 vinyl N -acetyl aziridines is also described.