Gold-Catalyzed Domino Cycloisomerization/Pictet-Spengler Reaction of 2-(4-Aminobut-1-yn-1-yl)anilines with Aldehydes: Synthesis of Tetrahydropyrido[4,3-b]indole Scaffolds

A domino cycloisomerization/Pictet-Spengler reaction of 2-(4-aminobut-1-yn-1-yl)aniline with aldehydes has been achieved using a AuIPrCl (5 mol %)/AgSbF6 (10 mol %) catalytic system to produce the corresponding 1-aryl-N-tosyl-2,3,4,5-tetrahydropyrido[4,3-b] indole derivatives in good yields. This is the first report on the synthesis of tetrahydro pyrido[4,3-b]indole scaffolds through as tandem 5-endo-dig cyclization and Pictect-Spengler reaction.