A novel synthesis of enantiopure octahydropyrrolo[3,4-b]pyrroles by intramolecular [3 + 2] dipolar cycloaddition on chiral perhydro-1,3-benzoxazines

reaction: see text] Condensation of N-substituted glycines with chiral 3-allyl-2-formyl perhydro-1,3-benzoxazines forms an azomethine ylide that cyclizes to give octahydropyrrolo3,4-b]pyrrole derivatives. The 3 + 2] dipolar cycloadditions are stereoespecific leading to a single diastereoisomer. The chemical yields are dependent on the reaction temperature and the presence or absence of a base.