2.11 Practices Answers

1. Label hemiacetal or acetal in the following structures.

2. Show the product of the following reactions.

a.

b.

c.

d.

e.

f.

g.

h.

3. Show the detailed steps for the following synthesis.

Tips: LiAlH₄ reduces ester to alcohol, however it reduces the ketone group as well. To ensure the reaction occurs only on the ester group selectively, the ketone group could be first protected by cyclic acetal, then deprotected after the reduction. So three steps are necessary for the overall synthesis, as shown below.