= Solution
The free allylic <alcohol> directs epoxidation of the adjacent <alkene> rather than the remote double bond. Applying the D-(−)-tartrate mnemonic gives \b[the <epoxide> <oxygen> on the back face in the source orientation], with both new C–O bonds dashed if the original six-membered ring is kept in the plane. The CH$_2$OH substituent at the lower <epoxide> <carbon> consequently projects towards the front in an explicit tetrahedral product drawing. The remote double bond is retained. The opposite tartrate would reverse both newly created <epoxide> <stereocentres>; it would not alter the location of the epoxidized <alkene>.
Back to article page
