Conformational studies of α-substituted ketones by nuclear magnetic resonance

Abstract

The nuclear magnetic resonance spectra are reported for a series of α-substituted 3-pentanones. Magnetically nonequivalent methylene hydrogens are observed whenever the substituent group is diamagnetically anisotropic. The results are discussed in terms of the possible conformations of the molecules; the most stable conformations are those with the C=O bond essentially eclipsed by the terminal methyl groups.