Imidazole was generated in situ via a domino reaction between glyoxal, formaldehyde, and two units of aqueous ammonia. Aqueous bicarbonate and a carboxylic anhydride or dialkyl dicarbonate were added, yielding the corresponding N,N′-diacyl or N,N′-dicarbalkoxy-2-hydroxyimidazoline. A Bamberger ring cleavage ensued, affording cis-1,2-di(acetamido)ethene, cis-1,2-di(propylamido)ethene, cis-1,2-di(ethoxyamido)ethene, cis-1,2-di(tert-butoxyamido)ethene, or cis-1,2-di(benzamido)ethene as easily isolable solids. The convenience and generality offered by this one-pot approach implied a cost-effective route to the routine synthesis of oligo- and polyvicinalamine precursors.
