Diastereoselective preparation of 2,4,6-trisubstituted-2'-cyanopiperidines: application to the construction of the carbon framework of perhydrohistrionicotoxin

Org Biomol Chem. 2003 Feb 7;1(3):547-51. doi: 10.1039/b209387a.

Abstract

The anodic cyanation of methanolic solutions of the 2-alkyl-N-phenylpiperidines 6b-d was performed in a flow cell equipped with a graphite felt anode. The reaction led to the formation of the 2-cyano-6-alkyl-N-phenylpiperidines 2b-d and proceeded with a high degree of regioselectivity. The 1H NMR spectra of the aminonitriles 2b-d showed an epimeric mixture at C-6. The major isomer has a trans configuration in which the cyano group is axial and the alkyl substituent is equatorial. Conversely, electrochemical oxidation of the 4-methyl-6-pentyl-N-phenylpiperidine 6e afforded the trisubstituted aminonitrile 2e as a single diastereomer (> 98% de). The 4-cyanobutyl side chain was incorporated in a two-step procedure to yield dinitrile 4e. This latter compound was directly converted into spiropiperidine 5e by using the Thorpe-Ziegler annulation procedure. The overall sequence (4 steps, 43%) allows the construction of the basic carbon framework of perhydrohistrionicotoxin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphibian Venoms / chemical synthesis
  • Amphibian Venoms / chemistry*
  • Cyanides / chemistry*
  • Models, Molecular
  • Neurotoxins
  • Piperidines / chemical synthesis*
  • Piperidines / chemistry
  • Spiro Compounds / chemistry
  • Stereoisomerism

Substances

  • Amphibian Venoms
  • Cyanides
  • Neurotoxins
  • Piperidines
  • Spiro Compounds
  • perhydrohistrionicotoxin