Let’s see what we came up with. The first intermediate will have a protective diether at the ketone
carbonyl. The second will show the reduction of the ester to an alcohol, with the protecting group
still present. The third will be our final product.
Reaction 2
If ethanol is reacted in acidic solution with potassium dichromate, what will the end product be?
hydroxyl groups. For the second reaction, we have a reducing agent in an organic solvent. Finally,
we have an acidic workup—which is often used to remove protecting groups. We’re starting to get
hints as to what is happening here.In the first reaction, both the ketone and ester carbonyls are highly reactive. One or both of
these functional groups will react in the first step.The diol is a good nucleophile because it contains lone pairs on the oxygen atoms in the
hydroxyl groups. Further, the presence of a diol hints at protecting the ketone carbonyl because
diols are commonly used for this function. This gives our first intermediate—the ketone carbonyl
will be replaced by a protected diether. The second reaction, then, will only be able to proceed on
the ester. LiAlH 4 is a strong reducing agent, so the next reaction will be reduction of the carbonyl
all the way to an alcohol. In the final reaction, the protecting group will be removed by acidic
workup, leaving us with our original ketone group.The product and intermediate have no stereoselectivity, so this won’t be a consideration.