T. Tezuka et al., STUDIES OF STERIC EFFECTS - SPECTROSCOPIC EVIDENCE FOR THROUGH-SPACE INTERACTION IN CH3----O IN CROWDED ALCOHOLS, Tetrahedron letters, 38(24), 1997, pp. 4223-4226
Through-space interaction of the gamma-methyl hydrogen with the oxygen
atom in crowded tertiary aliphatic alcohols generates an abnormally l
ow-field chemical shift in the O-17 NMR spectra. The intramolecular th
rough-space attractive interaction or hydrogen bonding interaction bet
ween the gamma-methyl hydrogen and the oxygen lone pair (CH3 ---- O) i
s proposed as the cause of this shift. By this interaction, the less p
olar C-O bond is generated. (C) 1997 Elsevier Science Ltd.