Acylnitrosoderivatives, which are obtained by oxidation of the corresponding hydroxamic acids with tetraalkylammonium iodate, react instantaneously in the presence of dihydropyridine 1 leading to the Diels-Alder adducts 4 and 5. These latter ones were transformed stereospecifically into the racemic diaminodideoxylyxose derivatives 8 and 9.