Abstract A number of 3-bromo-5, 6-dihydro-4H-1, 2-oxazine N-oxides have been synthesized and subjected to [3+ 2] cycloaddition with alkenes affording various types of products: 3-vinyloxazolines, isoxazoline N-oxides, and 3-functionalized 1, 2-oxazine N- oxides.