Conformational Preferences of 2-Methoxy, 2-Methylthio, and 2-Methylselenocyclohexyl-N,N-dimethylcarbamate:  A Theoretical and Experimental Investigation

Studies on the conformational equilibria of 2-methoxy, 2-methylthio, and 2-methylselenocyclohexyl-N,N-dimethylcarbamate are reported. DNMR spectroscopy experiments at 203 K provided the percentages of each conformer in equilibrium. Theoretical calculations using the MP2, B3LYP, and B971 methods with cc-pVDZ basis set were applied to determine the differences in energy between the conformers. The analysis of the potential energy surface (PES) for each conformer showed the presence of two rotamers. NBO analysis provided an explanation of the factors (hyperconjugative and steric interactions) that drive rotamer and conformer preferences.