Concise and Diversity-Oriented Route toward Polysubstituted 2-Aminoimidazole Alkaloids and Their Analogues

Alkaloids of the naamine family were synthesized from diverse propargylamines in just two steps (see scheme: R1=Me, R2=substituted benzyl, R3=Ar). Thus, the addition to a propargylamine of a carbodiimide generated in situ, silver(I)‐catalyzed intramolecular hydroamidation, and subsquent deprotection provide access to the heterocyclic core of numerous natural products and biologically active compounds. Boc=tert‐butoxycarbonyl, Cbz=carbobenzyloxy.