2-Cyano-Δ3-piperideines. 12. Stereochemistry of Formation of N-Benzyl-2-cyano-Δ3-piperideines and Facile Isomerization on Alumina to 2-Cyano-Δ4-piperideines. A Potentially General Route to the Synthesis of 2,6-Disubstitute

Article abstract of DOI:10.1021/jo00187a018

The reaction of the piperideine N-oxides 1a-f with trifluoroacetic anhydride in CH2Cl2 at 0 deg C (Polonovski-Potier reaction) led to the formation of the N-benzyl-2-cyano-Δ³-piperideines 3a-f.Epimeric mixtures were obtained for the amino nitri