| Abstract: | The ability of the equatorial C‐H bonds to form C‐H—O hydrogen bonds was studied by measuring the high‐pressure Raman spectra. We have investigated the effect of pressure versus C‐H—O interactions in 1,3‐dioxane/D2O mixtures. Dilution of 1,3‐dioxane leads to a shift of the C‐H signals to higher frequencies under ambient pressure. Based on the pressure‐dependence of the Raman spectra, we have found that the equatorial C‐H groups of 1,3‐dioxane displays a remarkably different ability to serve as the weak hydrogen bond donors in comparison to the axial C‐H of 1,3‐dioxane. The new Raman spectral features observed under high pressure may arise from the combined effect of hydrogen‐bond network changes, hydrogen bond‐like C‐H—O interactions formation, cluster size changes, etc. This finding may be important to diastereo‐ and enantioselective synthesis. |
