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. Copyright