| Abstract
| - To what extent, if any, is the conformation of secondary amides revealed by theory? This questionhas now been addressed by computational methods using calculations at the B3LYP/6-31G* levelof theory and 1H NMR spectroscopy. Both gas-phase and solvent studies predict a Z-anticonformation to be the lowest in energy for an evaluated series of acetamides. Moreover, Z-anticonformations may also be inferred from the chemical shifts of the N−CHα protons determined byNMR spectroscopy. Thus, a proton situated anti to the N−H proton consistently appears ∼0.8 ppmfurther downfield than a proton situated gauche to the N−H proton. This finding, which couldonly be derived by using the DFT calculations of conformational preference as a guide to interpretthe NMR data, might prove to be useful as a simple and convenient methodology for establishingamide conformation experimentally.
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