Show how you would convert the following starting materials into the target compound. You may use any additional reagents you need.

When treated with hydrogen and a platinum catalyst, an unknown compound X absorbs 5 equivalents of hydrogen to give n-butylcyclohexane. Treatment of X with an excess of ozone, followed by dimethyl sulfide and water, gives the following products:

Propose a structure for the unknown compound X. Is there any uncertainty in your structure?

The following functional-group interchange is a useful synthesis of aldehydes.

(c) Explain why a nucleophilic reagent such as ethoxide adds to an alkyne more easily than it adds to an alkene.

The following functional-group interchange is a useful synthesis of aldehydes.

(a) What reagents were used in this chapter for this transformation? Give an example to illustrate this method.

(b) This functional-group interchange can also be accomplished using the following sequence.

Propose mechanisms for these steps.

Show how you would synthesize the following compounds, starting with acetylene and any compounds containing no more than four carbon atoms.

g. pentanal, CH₃CH₂CH₂CH₂CHO

h. pentan-2-one, CH₃–CO–CH₂CH₂CH₃

i. (±) 3,4-dibromohexane

When compound Z is treated with ozone, followed by dimethyl sulfide and washing with water, the products are formic acid, 3-oxobutanoic acid, and hexanal.

Propose a structure for compound Z. What uncertainty is there in the structure you have proposed?

Using any necessary inorganic reagents, show how you would convert acetylene and isobutyl bromide to

(a) meso-2,7-dimethyloctane-4,5-diol, (CH₃)₂CHCH₂CH(OH)CH(OH)CH₂CH(CH₃)₂.