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The Regioselective 3-Alkylation Of Piperidine, Richard Dunn Todd

Chemistry & Biochemistry Theses & Dissertations

The compounds: 3-allylpiperidine, 3-ethylpiperidine and 3-n-butylpiperidine have been synthesized by regioselectively alkylating the three position of piperidine. Piperidine was converted to N-chloropiperidine and then dehydrohalogenated to produce Δ¹-piperideine. The enamide anion was generated by adding solutions of Δ¹-piperideine to ethylmagnesium bromide or lithium diisopropylamide. Addition of alkylhalides produced 3-alkyl- Δ¹-piperideine which could be reduced or alkyllithiated to give 3-alkylpiperidines or 2,3-dialkylpiperidines respectively.

The yields of products were low and the reaction generated a continuum of mono- and di-alkylpiperidines and there was evidence that several dimeric piperideines were formed. The low yields were discussed in …