Draw the intermediate in the following reaction.

Write the structures of the hemiacetal or hemiketal that result from reactions (a) and (b). Write the structures of the complete hydrolysis products of the acetal or ketal in (c) and (d).

a. Acetone + Ethanol → ?

What two products result from the complete hydrolysis of this cyclic acetal?

Acetals and ketals are usually made by reaction of an aldehyde or ketone with two molecules of a monoalcohol. If an aldehyde or ketone reacts with one molecule of a dialcohol, however, a cyclic acetal or ketal results.

b. Draw the cyclic ketal formed when the hemiketal from part (a) reacts with the ―OH labeled in blue.

What would be the product of the following reaction?

Draw the structure of the product when one mole of cyclopentanone reacts with two moles of methanol in an acidic solution.

Determine whether the following compounds are acetals or ketals. Draw the structure of the aldehyde or ketone it came from.

c.

Draw the structures of the hemiacetals or hemiketals formed in these reactions: 

b.

Cyclic hemiacetals commonly form if a molecule has both an alcohol group and a carbonyl group elsewhere in the same molecule, especially if they are four or five carbons apart. What is the structure of the hydroxy aldehyde from which this hemiacetal might form?