New development of synthesis of aromatic heterocycles using A novel palladium-phosphine ligand reagent

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1) Investigation of general synthetic method for chelerythrine type alkaloidA novel palladium reagent prepared from equimolar palladium acetate, DPPP, and tributylphophine was useful for the inernal biaryl coupling reaction of benzanilide possessing not only triflate but also halogen as a leaving group. By using this novel Pd reagent, benzo [c] phenanthridine alkaloids, chelerythrine, 12-methoxydihydrochelerythrine, and norchelerythrine were synthesized in good yields.. Benzo [d] naphtopyranones, arnottin I, was also synthesized by using typical Heck's reaction conditions.2) Mechanistic aspect of novel Palladium reagent [palladium acetate, DPPP, and tributylphophine]It was found out that molar ratio of Pd : phosphine=1 : 3 is essentially necessary for biaryl coupling reaction3) Synthesis of phenolic benzo [c] phenanthridine alkaloidFagaridine was synthesized in a good yield via biaryl coupling reaction of benzanilide protected by isopropyl group followed by reduction and acid treatment.4) Synthetic studies on Amaryllidaceae alkaloid, trisphaeridinePhenanthridine alkaloid, trisphaeridine, was synthesized via biaryl coupling reaction using palladium reagent.