Conformation, in solution, of c-4-t-butyl-1-phenyl-r-1-(N-piperidyl)cyclohexane hydrochloride. The conformational energy of t-butyl

✍ Scribed by Muthiah Manoharan; Ernest L. Eliel

• Publisher: Elsevier Science
• Year: 1984
• Tongue: French
• Weight: 137 KB
• Volume: 25
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)81359-9

✦ Synopsis

Although the hydrochloride of c-4-t-butyl-l-phenyl-c-l-(N-piperidyl)cyclohexane crystallizes in the conformation with axial-t-butyl, it exists as an almost equimolar mixture of the two chair conformers in CD-Cl_ solution. -The nosition of eauilibrium allows one to calculate AG:-Bu as -4.9 kcal/mol. z z

In 1981, Geneste et a1.l showed that the title compound (1) crystallizes in the conformation 1A with axial t-butyl, presumably because of a high tendency of the protonated and ion-paired piperidinium moiety to avoid the axial position. Surprisingly, however, it was also reported' that, in solution, 1 has the phenyl and t-butyl groups equatorial, i.e. exists as 1B.