A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N–O/N–N bond cleavages and two C–N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands
acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(III) intermediates were involved
Facile one-pot syntheses of amidines and enamines were achieved by trapping carbocation intermediates that were formed by Beckmann rearrangement of oximes with amines and carbon nucleophiles, respectively, under mild conditions.
Iminocarbocation intermediates were in situ-generated by treating various oximes with trifluoromethanesulfonic anhydride (Tf2O) in the presence of triethylamine in toluene and nucleophilic trapping with amines or sodium enolates under mild conditions afforded the corresponding amidines and enamines. Some of the thus-obtained enamines were converted to 2-substituted 4-oxo-3-quinolinecarboxylic acid derivatives by subsequent intramolecular Friedel–Crafts acylation.