Analysis of two carbon-13 NMR correlations for determining the stereochemistry of 1,3-diol acetonides

The stereochemistry of syn- and anti-1,3-diol acetonides can be assigned from the 13 C chemical shifts of the acetal methyl groups and from the 13 C chemical shifts of the acetal carbon. In general, the syn-1,3-diol acetonides have acetal methyl shifts at 19 and 30 ppm and acetal carbon shifts at 98.5 ppm, while the anti-acetonides have methyl shifts at 25 ppm and acetal shifts at 100.5 ppm. We have tested the generality and reliability of these two correlations by carrying out a complete literature search for 1,3-diol acetonides and identifying those with assignable 13 C spectra