Annulation Cascade of Sulfamate-Derived Cyclic Imines with Glycine Aldimino Esters: Synthesis of 1,3-Benzoxazepine Scaffolds.

An efficient (3 + 2) cycloaddition triggered annulation is reported to access 1,3-benzoxazepine frameworks. With amine base, sulfamate-derived cyclic imines readily react with glycine aldimino esters to furnish benzo-fused seven-membered heterocyclic products in good yields. The cascade reaction involves the formation of one C-C, one C-N, and one C-O bond along with the cleavage of two C-N bonds and one S-O bond. The synthesis of o-tyrosine analogues has also been accomplished from annulation products.