On the stereochemistry of piperidine quaternizations

✍ Scribed by A.T. Bottini; M.K. O'Rell

• Publisher: Elsevier Science
• Year: 1967
• Tongue: French
• Weight: 239 KB
• Volume: 8
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)90962-6

✦ Synopsis

Seemingly contradictory conclusions were reached recently by two groups who studied the s-tereochemistry of qunternizations of 4-substituted piperidines. For example, House, Tefertiller, and Pitt (2) reported that quaternization of I!-s-butyl-1-ethylpiperidine with methyl tosylate in acetonitrile gave a 4:l ratio of diastereomeric products, and they concluded that the major product was formed from the more stable equatoriall-ethyl conformer. On the other hand, Imbach, Katritzky, and Kolinski (3) reported that quaternization of 4-phenyl-l-ethylpiperidine with methyl iodide gave a 12.5:1 product ratio, and they concluded that the major product was formed from the less stable axial-l-ethyl conformer. Similar stereoselectivity has been observed for quaternization reactions in methanol of 1,2,3-trial~~laziridines with deuteriomethyl benzenesulfonate