Stereochemical aspect of heating of cyclohexane-1,2-diol Does stereochemistry play any role in the heating of Cyclohexane-1,2-diol?

If I remember correctly, different products are formed depending on whether the diol is cis or trans. (I think the products are cyclohexanone and cyclopentanecarbaldehyde). Please clarify this along with the reason why different products are formed depending on the stereochemistry.
The reaction you are thinking of is likely the thermal decomposition of the cyclic sulfites prepared from the cis- and trans-diols.  Here is a link to the abstract.



In both reactions $\ce{SO2}$ is extruded.  Whichever group on the vicinal carbon that is lined up in an anti-periplanar fashion to the departing oxygen is the group that migrates.  This is because the antiperiplanar geometry allows for good orbital overlap during the migration; if a choice is available then hydrogen migrates in preference to an alkyl group just as with carbocations. In the cis-isomer, the vicinal hydrogen is properly aligned (I darkened the affected bonds to highlight the geometric arrangement), its migration produces cyclohexanone.  In the trans-isomer, only a $\ce{C-C}$ bond in the cyclohexane ring is properly aligned, its migration produces cyclopentanecarbaldehyde.