Palladium(0)-catalyzed heteroarylation of 2- and 3-indolylzinc derivatives: an efficient and general method for the preparation of (2-pyridyl)indoles and their application to indole alkaloid synthesis

A series of (2-pyridyl)indoles was synthesized from the palladium(0)-mediated reaction of (1-(tert-nutyldimethylsilyl)-3- indolyl)zinc chloride and (1-(benzenesulfonyl)-2-indolyl)zinc chloride. The resulting products were utilized for the synthesis of the indolo[2,3-alpha]quinolizidine system via the stereoselective hydrogenation of thge pyridine ring followed by electrophilic cyclization in the indole 3-position.