I. Silver Catalyzed Synthesis of Isoquinoline via Redox Reaction II. Studies toward synthesis of fumaria Alkaloids via Gold-catalyzed Redox Cascade

Abstract

Part I. Silver-catalyzed synthesis of isoquinoline via redox reaction Under AgOTf and Brønsted acid co-catalysis, O-alkyl o-alkynylbenzaldoxime derivatives undergo a cyclization-induced N-O cleavage to produce isoquinolines with the simultaneous oxidation of O-alkyl group. This redox-based method provides a general access to diverse isoquinoline-derived heterocycles that are simple, efficient and tolerant of various functional groups from readily available and hydrolytically stable oxime precursors.

Part II. Studies toward the synthesis of Fumaria alkaloids gold-catalyzed redox cascade Synthesis of fumaritrine has been achieved by Miyoji and co-workers by the transformation of protoberberines into benzindenoazepines. We were trying to synthesize isoquinoline product which would be the synthetic intermediate of Miyoji’s by gold-catalyzed intramolecular redox reaction with substrates having alkynes and nitrons. However, we failed to synthesize the key intermediate toward fumaritrine due to the difficulty of cross-coupling and/or condensation of nitrone, forming strained 10 membered ring. For the case of synthesizing bulgaramine, the reaction did not go as we expected, but found a new cyclization product using Pd catalyst.