Peculiarities of electroreduction of trans-2-allyl-6-methyl(allyl,phenyl)-1,2,3,6-tetrahydropyridines

Electrochemical reduction of trans-2-allyl-6-R-1,2,3,6-tetrahydropyridines (R = Me, All, and Ph) on the mercury cathode in anhydrous DMF (with 0.1 M B u4NClO4 as the supporting electrolyte) resulted in catalytic hydrogen evolu tion, while in the case of anhydrous DMF the electrochemical activity of th e endocyclic double bond was dictated by the nature of the R substituent at the carbon atom neighboring the double bond. The electrocatalytic hydrogen ation of the piperideines under study on the Ni (Ni-disp/Ni) cathode in 40% ; aqueous DMF in the presence of a tenfold excess of AcOH yielded the corre sponding trans-2-propyl-6-R-1 piperidines (R-1 = Me, Pr, acid Ph). Using tr ans-2,6-diallyl-1,2,3,6-tetrahydropyridine as an example, the conditions (w ith annealed copper as the cathode) for selective hydrogenation of the doub le bonds in allyl substituents with preservation of the endocyclic double b ond were found.