10. Addition Reactions

What reagents should be used to carry out the following syntheses?

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

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?

(a)

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)

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.

c. hex-1-yne

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.

(c) oct-1-yne

How can the following compounds be synthesized, starting with a hydrocarbon that has the same number of carbons as the desired product?

c.

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.

e. 3-methylcyclodecyne

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

Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.

e. aqueous H₂SO₄, HgSO₄

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

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

(c)

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