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

Abstract

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).