10. Addition Reactions

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

f. R₂BH in THF followed by H₂O₂/HO⁻ /H₂O

Predict the major products of the following reactions.

d. trans-cyclodecene + peroxyacetic acid in acidic water

e. cis-cyclodecene + mCPBA in CH₂Cl₂, then dilute aqueous acid

For each compound, give the product(s) expected from (1) HgSO₄/H₂SO₄ - catalyzed hydration and (2) hydroboration–oxidation.

d. cyclodecyne

For each compound, give the product(s) expected from (1) HgSO₄/H₂SO₄ - catalyzed hydration and (2) hydroboration–oxidation.

c. hex-3-yne

For each compound, give the product(s) expected from (1) HgSO₄/H₂SO₄ - catalyzed hydration and (2) hydroboration–oxidation.

b. hex-2-yne

For each compound, give the product(s) expected from (1) HgSO₄/H₂SO₄ - catalyzed hydration and (2) hydroboration–oxidation.

a. hex-1-yne

The hydroboration–oxidation of internal alkynes produces ketones.

b. When hydroboration–oxidation is applied to pent-2-yne, two products are obtained. Show why a mixture of products should be expected with any unsymmetrical ­internal alkyne.

The hydroboration–oxidation of internal alkynes produces ketones.

a. When hydroboration–oxidation is applied to but-2-yne, a single pure product is obtained. Determine the structure of this product, and show the intermediates in its ­formation.

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

j. trans-hex-2-ene → cis-hex-2-ene

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

j. NaNH₂

k. H₂SO₄/HgSO₄, H₂O

l. Sia₂BH, then H₂O₂, ^–OH

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

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For the alkynes shows here, show the product(s) expected to form when treated under the following conditions: (vii) 1. BH₃ 2. H₂O₂, NaOH. If you expect two products, show both.

(c)

Predict the product of the following aldehyde/ketone syntheses.

(c)

How can the following compounds be prepared using ethyne as the starting material?

a.