One‐Pot Tandem Protocol for the Synthesis of 1,3‐Bis(β‐aminoacrylate)‐Substituted 2‐Mercaptoimidazole Scaffolds

We have developed a palladium‐catalyzed cross‐coupling reaction of isocyanides with α‐diazoacetates to form active ketenimines and following a 1,4‐diazabicyclo[2.2.2]octane (DABCO) catalyzed aza‐Mannich type reaction with various 2‐mercaptoimidazoles for the synthesis of 1,3‐bis(β‐aminoacrylate)‐substituted 2‐mercaptoimidazole derivatives with structural diversity. In addition, the use of 1 H ‐benzo[ d ]imidazol‐2‐ol as the reaction partner also allowed the formation of 1,3‐bis(β‐aminoacrylate)‐substituted 2‐benzimidazolinone derivatives with moderate yields (34–52%). In the aza‐Mannich reaction, the regioselective N ‐attack rather than S ‐attack or O ‐attack at the electrophilic central carbon of ketenimines was observed. This tandem sequence is efficient since two C=C and two C−N bonds are consecutively created in one‐pot.