Alkyne Hydroboration Practice Problems

Draw the ketone that is expected to be formed when the alkyne shown below undergoes the hydroboration-oxidation reaction.

Identify the two alkynes that can be used in the synthesis of the following ketone, and determine if it can be synthesized in a high yield utilizing any of the two reactions. If not, draw all the possible products.

What are the product(s) for the reaction of the given alkyne with (1) BH  ₃, H₂O₂, and (2) NaOH?

Using acetylene, (2-bromoethyl)benzene, and any other reagents, propose a synthesis of the following alkene.

Retrosynthetic analysis involves the reverse process of designing the synthesis of a novel compound, which is usually a multi-step process. For this problem, using only one-step retrosynthesis, propose an alkene and the reagents needed to produce the desired products without involving alkenes that will undergo rearrangement.

Retrosynthetic analysis is a process that is the reverse of designing the synthesis of a novel compound, which usually takes a multistep process. Using only a one-step retrosynthesis, propose an alkene and the reagents needed to produce the desired product. (Note: the alkene should not undergo rearrangement.)

Retrosynthetic analysis is a process that is the reverse of designing the synthesis of a novel compound, which usually takes a multistep process. Using only one-step retrosynthesis, propose an alkene and the reagents needed to produce the product given below. (Note: the alkene should not undergo rearrangement.)

Using the starting material below, propose the synthesis of the product using 3 steps.

Note: While multiple approaches may exist to achieve each synthesis, the minimum steps required are indicated above each reaction arrow.

How can you synthesize the following alkyne by combining an alkyne with an alkyl halide?  (The following alkyne can be synthesized in two ways.)

Propose a synthesis of the molecule on the right, starting with the molecule on the left. Although there may be other synthetic routes that are worthwhile, the ideal number of steps is indicated over the reaction arrow.

How can the given compound be produced from an organic molecule with no more than three carbons?

Determine the synthesis of the given compound starting  with an organic compound with three carbons or less.

A chloroketone is synthesized when alkynes are reacted with water and chlorine. Determine the arrow-pushing mechanism that explains how the product formed.

What is the product of the given reaction?

Design a multistep synthesis to produce the following target molecule using the given starting material.

Design a multistep synthesis to show how the following target molecule can be produced using the given starting material.

Compound A with the molecular formula C₇H₁₂ has an ethyl group and a cyclic ring. It reacts with one equivalent of H₂, Pd/C to produce B. The hydroboration-oxidation reaction of A produces a pair of enantiomers, C and D. After the ozonolysis of A, a reaction with dimethyl sulfide produces E with the chemical formula C₇H₁₂O₂, which contains one aldehyde and one ketone functional group. Draw the structures for A–E.

Determine the major products of the reactions given below, and include stereochemistry if applicable.

Determine the major products of the reactions given below and specify their stereochemistry.

Determine the correct reagents needed for the following reactions.

A) (I) Br₂, H₂O (II) HBr

B) (I) HBr (II) Br₂, H₂O

C) (I) Br₂, CCl₄ (II) Br₂, H₂O

D) (I) HBr (II) HBr, peroxide

Identify the reagents required for the following reactions.

Determine the appropriate reagents for the following reactions.

Determine the reagents needed for the following reactions.

Determine the major products of the reactions given below, and include stereochemistry if applicable.

Write the synthesis of the given compound, starting with  1-ethylcyclopent-1-ene. 

Start with cyclopentene and write the possible reaction sequence to prepare the compound given below.

Write a possible reaction sequence to synthesize the following aldehyde from the given alkyl halide.

Determine how cis-3-heptene can be synthesized starting from butyne.

Provide the synthesis of pentan-2-one using propyne, any inorganic reagents, and any organic compounds with fewer than four carbons.

Describe the steps required to make hexan-3-ol using but-1-yne, any inorganic reagents, and any organic molecule with less than four carbons.

Write the synthesis of the following compound from the provided starting material. Include the structures of the intermediate products.

Determine the reagents required to perform the following reaction.

Provide the reagents that will be required to carry out the given reaction.

Provide the reagents needed to complete the following reaction.

Determine the reagents that are required for the following reactions.

The reactant in a stereospecific reaction must have stereoisomers. True or false?

For each reaction in the sequence below, write the correct reagent:

For each reaction in the following sequence, write the suitable reagent:

For each reaction in the sequence given below, write the proper reagent:

How can 1-ethylcyclohexanol be prepared, starting with ethynylcyclohexane? Write the structure of the second alcohol that would also be obtained as a product.

Which of the following electrophilic addition reactions forms a carbocation intermediate?

Which of the following electrophilic addition reactions forms a three-membered ring ?

Which of the following electrophilic addition reactions forms a five-membered ring intermediate?

Identify the correct statement for the acid-catalyzed hydration reaction of 1-pentene.

What would be the final yield of the following synthesis, if the percentage yield of each step is 60%?

Provide appropriate reagents to carry out each of the following reactions.

Determine the major product formed when 3-hexyne reacts with H₂O, aqueous H₂SO₄, and HgSO₄.

Determine the major product formed when 3-hexyne reacts with R₂BH in THF, followed by H₂O₂, OH⁻, and H₂O.

Explain why HO− and HOOH cannot be added to the hydroboration-oxidation reaction until the hydroboration reaction is complete.

How is pentan-2-one made from a hydrocarbon with the same number of carbon atoms as the expected product?

An unknown compound X absorbs 5 equivalents of hydrogen to give n-butylcyclopentane when it is treated with hydrogen gas in the presence of a platinum catalyst. The following products are obtained when X is treated with an excess of ozone, followed by dimethyl sulfide and water.

Propose a structure for the unknown compound X. Is there any uncertainty in the structure that you proposed?

An unknown alkene reacts with three equivalents of hydrogen gas (H₂) to give isopropylcyclohexane in the presence of a platinum catalyst. Deduce the structure of the unknown alkene if the following are the products obtained when it is ozonized and reduced.

Suggest a plausible mechanism for the reaction shown below.

Determine the identity of products obtained in the reaction of but-1-yne with each of the reagents shown below.
(i) HBr (1 equivalent)
(ii) HBr (2 equivalents)
(iii) H₂ (excess), Pt catalyst

Determine the identity of products obtained in the reaction of but-1-yne with each of the reagents shown below.
(i) H₂, Pd/BaSO₄ catalyst, quinoline
(ii) Br₂ (1 equivalent)
(iii) Br₂ (2 equivalents)

Determine the identity of products obtained in the reaction of but-1-yne with each of the reagents shown below.
(i) dilute, cold solution of KMnO₄
(ii) concentrated warm solution of KMnO₄ and NaOH, then HCl
(iii) Na in liquid NH₃

Determine the identity of products obtained in the reaction of but-1-yne with each of the reagents shown below.
(i) NaNH₂
(ii) HgSO₄/H₂SO₄, H₂O
(iii) Sia₂BH, followed by H₂O₂, ⁻OH

Show how you can make these compounds from but-1-yne.
(i) 1,2-dibromobut-1-ene
(ii) 1-bromobut-1-ene
(iii) 2-bromobut-1-ene

Show how the following transformation can be accomplished.
2-bromo-2-methylpentane → 2-methylpentan-3-ol

Show how the following transformation can be accomplished.
1-methylcyclohexanol → 2-methylcyclohexanol

Show how the following synthetic conversion can be accomplished.

Propose a synthesis plan for the following compound. You can use any alkenes or cycloalkenes that contain no more than six carbon atoms as the starting material.

Using but-1-ene as your starting material, show how the following compounds can be synthesized.
(i) but-2-yne
(ii) butan-2-one
(iii) butanal

Using but-1-ene as your starting material, show how the following compounds can be synthesized.
(i) propanoic acid
(ii) propanal
(iii) hept-4-yn-3-ol

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
2,2-dibromopentane → pent-1-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
2,2-dibromopentane → pent-2-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
pent-1-yne → oct-4-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
trans-but-2-ene → but-2-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
2,2-dibromobutane → but-1-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
pent-2-yne → cis-pent-2-ene

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
but-1-yne → butanal

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
trans-but-2-ene → cis-but-2-ene

Examine the following reactions and predict the major products. 

Examine the following reactions and predict the major products.

Predict the reagents for the following reaction.

Predict the reagents for the following reactions.

Draw the reaction intermediates and major products for the following reactions.
Show the stereochemistry where applicable.

Provide the missing products, in each step of the given synthesis. Include any important stereochemistry.

Provide the missing products in each step of the given synthesis and show any important stereochemistry.

Hydroboration-oxidation of internal alkynes produces ketones while the same reaction for terminal alkynes produces aldehydes. Draw the final product when ethynylcyclohexane is subjected to hydroboration-oxidation. Additionally, show any intermediates.

Hydroboration-oxidation of internal alkynes produces ketones while the same reaction for terminal alkynes produces aldehydes. Draw the final products when 1-cyclohexyl-1-propyne is subjected to hydroboration-oxidation. Describe why hydroboration-oxidation of an unsymmetrical internal alkyne results in a mixture of products.

For the compound shown below, predict products that result when it undergoes the following:
a. Acid-catalyzed hydration
b. Hydroboration-Oxidation

For the compound shown below, predict products that result when it undergoes the following:
a. Acid-catalyzed hydration
b. Hydroboration-Oxidation

For the compound shown below, predict products that result when it undergoes the following:

a. Acid-catalyzed hydration
b. Hydroboration-Oxidation

For the compound shown below, predict products that result when it undergoes the following:
a. Acid-catalyzed hydration
b. Hydroboration-Oxidation

Determine the final products expected in each of the reactions given below.

Propose a synthesis plan for the following compound. You can use any alkenes or cycloalkenes that contain no more than six carbon atoms as the starting material.

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
pent-2-yne → trans-pent-2-ene