A general route to 1,2-oxazines and open chain oximes bearing a 1H-tetrazolyl substituent via Diels–Alder reaction of 3-(tetrazol-5-yl)-nitrosoalkenes is reported. It was also demonstrated that reduction of these adducts followed by deprotection of the tetrazolyl group give 5-(1-aminoalkyl)-1H-tetrazoles, α-amino acid analogues.