Straightforward Access to Hexahydropyrrolo[2,3‐b]indole Core by a Regioselective C3‐Azo Coupling Reaction of Arenediazonium Compounds with Tryptamines

A base‐mediated regioselective electrophilic addition of arenediazonium salts at the C3‐position of tryptamines followed by cyclization provides an efficient entry to C3‐nitrogenated hexahydropyrrolo[2,3‐b]indoles (HPIs) that can subsequently be transformed into 3‐arylhexahydropyrrolo[2,3‐b]indoles and other HPI derivatives. The reaction is the first example of a 1,2‐diamination that utilizes easily accessible arenediazonium salts as nitrogenous electrophiles.