13C Nuclear Magnetic Resonance Studies. XX. 13C Shieldings of Several Allyl Alcohols. Geometric Dependence of 13C Shieldings

The 13C spectra of 21 methyl- and halo-substituted 2-propenols have been determined. The shielding data are discussed with particular emphasis on their dependence on the orientation of the 3-halo substituents. Linear regression analyses of the results gave sets of additive parameters which correlate the shieldings with reasonable precision (≤ 1 p.p.m.). A similar set of parameters has been generated from the published data for acyclic alkenes: these parameter sets are intercompared. The results of complete analysis of the proton spectra of most of the alcohols are also presented.