Nuclear Magnetic Resonance Experiments on Acetals. 36. Proton Magnetic Resonance Spectra and Quantitative Conformational Data in 5-Fluoromethylated-5′-Me-1,3-Dioxanes

A proton magnetic resonance study of [Formula: see text] and 5-CH2F-5′-Me-1,3-dioxanes and the corresponding 2-Me-substituted derivatives enables approximate conformational insights. The system prefers an equatorial polar substitutent at C-5. This is very pronounced for CHF2, and to a lesser but still important extent for CH2F (ΔΔH0 = 488 cal/mol; ΔΔS0 = −3.0 e.u.).