STEREOSELECTIVE SYNTHESIS OF SUBSTITUTED PIPERAZINES

The treatment of allylarylamines with mercury(II) acetate in tetrahydrofuran followed by a double decomposition reaction with potassium bromide leads to trans‐2,5‐bis(bromomercuriomethyl)‐1,4‐diarylpiperazines (2). The stereochemistry of the reaction products has been elucidated by an 1H‐nmr spectroscopic study of the trans‐2,5‐dimethyl‐1,4‐diarylpiperazines (3) obtained by sodium borohydride reduction of 2 in alkaline media. The course of the reaction strongly depends on the steric demand of the groups attached to either the allylic group or the ortho‐position in the aromatic ring of the starting amine (1). Copyright © 1979 Journal of Heterocyclic Chemistry