Alkenes cis, trans isomerism

Sometimes, an alkene cis-trans isomerization is observed during the oxidation of allylic alcohols with active Mn02. This side reaction occurs during the oxidation of allylic alcohols with many different oxidants. In fact, active Mn02 is quite refractory to induce such isomerizations,73 when alkene isomerizations must be avoided being the oxidant of choice. The addition of Na2C03 and the performance of the oxidation at 0°C help to prevent such isomerizations.74... 

---