21. Aldehydes and Ketones: Nucleophilic Addition

Provide the major product for the following reaction. 

Provide the major product for the following reaction. 

Provide the chemical steps necessary for the following synthesis.

Provide the major product for the following reaction dealing with the Grignard reagent.

Show how the following transformations may be accomplished in good yield. You may use any additional reagents that are needed.

(c) benzoic acid → phenyl cyclopentyl ketone

(d) 1-bromohept-2-ene → oct-3-enal

(•••) Predict the product and draw the mechanism for the acid-catalyzed pinacol rearrangement of the following diols.

(c) <IMAGE>

Alcohols combine with ketones and aldehydes to form

interesting derivatives, which we will discuss in Chapter 18.

The following reactions show the hydrolysis of two

such derivatives. Propose mechanisms for these reactions.

(b) <IMAGE of reaction>

In the mechanism for acetal hydrolysis shown, the ring oxygen

atom was protonated first, the ring was cleaved, and then

the methoxy group was lost. The mechanism could also

be written to show the methoxy oxygen protonating

and cleaving first, followed by ring cleavage.

Draw this alternative mechanism.