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Enantioselective Phase-Transfer-Catalyzed Intramolecular Aza-Michael Reaction: Effective Route to Pyrazino-Indole Compounds


  • Acknowledgements are made to the MIUR (Rome), Consorzio C.I.N.M.P.I.S., and University of Bologna. We kindly thank Dr. Paolo Melchiorre (University of Bologna) for helpful discussions.


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Producing polycycles: A mild and direct stereocontrolled route to pharmacologically active pyrazino-indol-1-ones has been developed. The optimal phase-transfer conditions provide variously functionalized ring-closed compounds in high chemical and optical yields (see scheme; X=H, F, Cl, Me, OMe; Ar=Ph, β-naphthyl; R′=tBu, Et, Me; R=benzyl, para-methoxyphenyl).