Synthesis of hydrazinoheterocycles from Morita-Baylis-Hillman adducts of nitroalkenes with azodicarboxylates

Conjugated nitroalkenes and nitrodienes undergo smooth alpha-hydrazination with azodicarboxylates through an imidazole catalyzed carbon-heteroatom bond formation under Morita-Baylis-Hillman conditions. The resulting hydrazinonitroalkenes take part in 1,3-dipolar cycloaddition with azide under mild conditions to give hydrazinotriazoles. A [3 + 2] annulation with phenols and naphthols involving Michael addition and cyclization as the key steps lead to arenodihydrofurans bearing a key hydrazinodicarboxylate moiety. Both regioisomers of naphthodihydrofurans could be synthesized by our methodology by employing the appropriate naphthol.