$$\text{C}_4\text{H}_9\text{Br}$$

$$1) \text{BH}_3 \cdot \text{THF} \\ 2) \text{NaOH}, \text{H}_2\text{O}_2$$

Question 1

Which reagent is used to deprotonate acetylene in the first step of the synthesis of 1-hexanol from acetylene?

Accepted Answer

$$	ext{NaNH}_2$$

Question 2

In the synthesis of 1-hexanol from acetylene, which alkyl halide is used to extend the carbon chain to six carbons?

Accepted Answer

$$	ext{C}_4	ext{H}_9	ext{Br}$$

Question 3

What is the purpose of Lindlar's catalyst in the synthesis of 1-hexanol from acetylene?

Accepted Answer

To selectively hydrogenate the alkyne to a cis-alkene

Question 4

Which sequence of reagents is used to convert the terminal alkene to a primary alcohol in the final step of the synthesis?

Accepted Answer

$$1) 	ext{BH}_3 \cdot 	ext{THF} \ 2) 	ext{NaOH}, 	ext{H}_2	ext{O}_2$$

Question 5

Which of the following best describes the overall transformation from acetylene to 1-hexanol?

Accepted Answer

Chain extension, partial hydrogenation, hydroboration-oxidation

Question 6

If you used $$	ext{Br}_2$$ instead of Lindlar's catalyst after chain extension, what would be the major product?

Accepted Answer

A trans-alkene

Question 7

Why is hydroboration-oxidation preferred over acid-catalyzed hydration for converting the terminal alkene to 1-hexanol?

Accepted Answer

It gives the anti-Markovnikov alcohol

Question 8

Which step in the synthesis is responsible for the anti-Markovnikov addition of the hydroxyl group?

Accepted Answer

Hydroboration-oxidation

Question 9

What would be the result if you used $$	ext{Pd/C}$$ instead of Lindlar's catalyst in the hydrogenation step?

Accepted Answer

The alkyne would be fully reduced to an alkane

Question 10

Which of the following is the correct order of steps for synthesizing 1-hexanol from acetylene?

Accepted Answer

Deprotonation, alkylation, partial hydrogenation, hydroboration-oxidation

Question 11

If you started with $$	ext{CH}_3	ext{Br}$$ instead of $$	ext{C}_4	ext{H}_9	ext{Br}$$, what would be the final product after all steps?

Accepted Answer

Question 12

Which inorganic reagent is essential for the initial deprotonation of acetylene?

Accepted Answer

$$	ext{NaNH}_2$$

Question 13

What is the role of $$	ext{BH}_3 \cdot 	ext{THF} in $$the synthesis?

Accepted Answer

It adds across the double bond in an anti-Markovnikov fashion

Question 14

Which product is formed after the alkylation step with $$	ext{C}_4	ext{H}_9	ext{Br}$$?

Accepted Answer

1-hexyne

Question 15

What is the function of $$	ext{NaOH}$$ and $$	ext{H}_2	ext{O}_2 in $$the hydroboration-oxidation step?

Accepted Answer

To oxidize the boron intermediate to an alcohol

Question 16

Which of the following is NOT a plausible intermediate in the synthesis of 1-hexanol from acetylene?

Accepted Answer

Hexanone

Question 17

If the hydroboration-oxidation step is omitted, what is the major product after Lindlar's hydrogenation?

Accepted Answer

1-hexene

Question 18

Which step in the synthesis is most likely to result in a mixture of products if not carefully controlled?

Accepted Answer

Hydrogenation with Lindlar's catalyst

Question 19

Which of the following best explains why acetylene is used as the starting material in this synthesis?

Accepted Answer

It allows for chain extension via alkylation

Question 20

What is the final product of the synthesis described in the study materials?

Accepted Answer

1-hexanol

Stepwise Synthesis of 1-Hexanol from Acetylene

Study Guide - Practice Questions