The application box in the margin of states, “The addition of an acetylide ion to a carbonyl group is used in the synthesis of ethchlorvynol, a drug used to cause drowsiness and induce sleep.” Show how you would accomplish this synthesis from acetylene and a carbonyl compound.

Muscalure, the sex attractant of the common housefly, is cis-tricos-9-ene. Most syntheses of alkenes give the more stable trans isomer as the major product. Devise a synthesis of muscalure from acetylene and other compounds of your choice. Your synthesis must give specifically the cis isomer of muscalure.

Predict the products of reaction of pent-1-yne with the following reagents.

a. 1 equivalent of HCl

b. 2 equivalents of HCl

c. excess H₂, Ni

Predict the products of reaction of pent-1-yne with the following reagents.

d. H₂, Pd/BaSO₄, quinoline

e. 1 equivalent of Br₂

f. 2 equivalents of Br₂

Predict the products of reaction of pent-1-yne with the following reagents.

g. cold, dilute KMnO₄

h. warm, concd. KMnO_4, NaOH

i. Na, liquid ammonia

Predict the products of reaction of pent-1-yne with the following reagents.

j. NaNH₂

k. H₂SO₄/HgSO₄, H₂O

l. Sia₂BH, then H₂O₂, ^–OH

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

a. 2,2-dibromobutane → but-1-yne

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

b. 2,2-dibromobutane → but-2-yne

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

c. but-1-yne → oct-3-yne

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

d. trans-hex-2-ene → hex-2-yne

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

e. 2,2-dibromohexane → hex-1-yne

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

f. cyclodecyne → cis-cyclodecene

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

g. cyclodecyne → trans-cyclodecene

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

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

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

i. hex-1-yne → hexanal, CH₃(CH₂)₄CHO

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

j. trans-hex-2-ene → cis-hex-2-ene

Show how you would synthesize the following compounds from acetylene and any other needed reagents:

(a) 6-phenylhex-1-en-4-yne

(b) cis-1-phenylpent-2-ene

Predict the products formed when CH₃CH₂–C≡C:^–Na⁺ reacts with the following compounds.

a. ethyl bromide

b. tert-butyl bromide

c. formaldehyde

Predict the products formed when CH₃CH₂–C≡C:^–Na⁺ reacts with the following compounds.

(d) cyclohexanone

(e) CH₃CH₂CH₂CHO

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

a. hex-1-yne

b. hex-2-yne

c. cis-hex-2-ene

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

d. trans-hex-2-ene

e. 1,1-dibromohexane

f. 2,2-dibromohexane

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 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?

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?

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

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.

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.

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.

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

(b) (±)-2,7-dimethyloctane-4,5-diol.

Deduce the structure of each compound from the information given. All unknowns in this problem have molecular formula C₈H₁₂.

(a) Upon catalytic hydrogenation, unknown W gives cyclooctane. Ozonolysis of W, followed by reduction with dimethyl sulfide, gives octanedioic acid, HOOC–(CH₂)₆–COOH. Draw the structure of W.