10. Addition Reactions

Only one alkyne forms an aldehyde when it undergoes the mercuric-ion-catalyzed addition of water. Identify the alkyne.

Show how you would accomplish the following synthetic transformations. Show all intermediates.

h. hex-1-yne → hexan-2-one, CH₃COCH₂CH₂CH₂CH₃

Draw the ketone(s) you would expect to form by reacting the following alkynes under the conditions of oxymercuration: (a) 6-methyloct-1-yne, (b) 1,10-dicyclohexyldec-5-yne, and (c) 5-phenylhex-2-yne.

Show how you would synthesize octanal from each compound. You may use any necessary reagents.

(e) 1-bromohexane

Show how you would synthesize octanal from each compound. You may use any necessary reagents.

(c) oct-1-yne

Hydration of alkynes (via oxymercuration) gives good yields of single compounds only with symmetrical or terminal alkynes. Show what the products would be from hydration of each compound.

b. hex-2-yne

Hydration of alkynes (via oxymercuration) gives good yields of single compounds only with symmetrical or terminal alkynes. Show what the products would be from hydration of each compound.

a. hex-3-yne

Predict the reagents or reactant(s) necessary to complete the following syntheses.

(c)

For each of the following ketones/aldehydes, indicate whether it is possible to synthesize it from an alkyne as the only compound in good (> 50%) yield. If so, how would you do it?

(d)

Which alkyne should be used for the synthesis of each of the following ketones?

a.

b.

Which alkyne should be used for the synthesis of each of the following ketones?

c.

Show how each of the following compounds can be prepared using the given starting material, any needed inorganic reagents, and any ­organic compound that has no more than four carbons:

e.

What ketones are formed from the acid-catalyzed hydration of 3-heptyne?

What are products of the following reactions?

f.