Electrochemical access to 8-(1-phenyl-ethyl)-1,4-dioxa-8-aza-spiro[4.5]decane-7-carbonitrile. Application to the asymmetric syntheses of (+)-myrtine and alkaloid (+)-241D

J Org Chem. 2014 Apr 18;79(8):3358-73. doi: 10.1021/jo500104c. Epub 2014 Apr 3.

Abstract

The total syntheses of both enantiomers of trans-quinolizidine (+)-myrtine and cis-2,4,6-trisubstituted piperidine alkaloid (+)-241D are reported here. Our approach was based on the N-Boc-directed metalation of enantiopure 4-piperidone (-)-11, which was prepared in four steps from α-amino nitrile 6 through a stereoselective alkylation-reduction decyanation process. α-Amino nitrile 6 was prepared at the anode through electrochemical oxidation of 4-piperidone (+)-5. In our study, α-phenylethylamine (α-PEA) allowed an efficient 1-3 stereoinduction, and an orthogonal cleavage of the N-Boc protecting group in piperidone derivatives was carried out by stirring them in a suspension of SnCl4·(Et2O)2 complex in diethyl ether. When appropriate, the er's were determined by proton and carbon NMR spectroscopy utilizing (+)-tert-butylphenylphosphinothioic acid and (+)-DBTA as chiral solvating agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids / chemical synthesis*
  • Alkaloids / chemistry
  • Catalysis
  • Electrochemistry
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Nitriles / chemical synthesis*
  • Nitriles / chemistry*
  • Quinolizines / chemical synthesis*
  • Spiro Compounds / chemical synthesis*
  • Spiro Compounds / chemistry*
  • Stereoisomerism

Substances

  • 8-(1-phenyl-ethyl)-1,4-dioxa-8-aza-spiro(4.5)decane-7-carbonitrile
  • Alkaloids
  • Nitriles
  • Quinolizines
  • Spiro Compounds
  • myrtine