Diastereoselective electrophilic bromination of 3,6-dihydro-2H-1,2-oxazines syn-1 and anti-1 led to 5-bromo-1,2-oxazin-4-ones 2a and 3a, respectively. Reduction furnished 1,2-oxazin-4-ones 4 and 6 which could be transformed into enantiopure amino and imino sugar derivatives. Nucleophilic substitution of the bromo functionality gave amino substituted 1,2-oxazines 10. They were converted into diamino substituted sugar derivatives.