Skip to main content
Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Bruice 8th EditionCh. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis문제 17a
7장, 문제 17a

For each of the following alkynes, draw the products obtained from (1) the acid-catalyzed addition of water (mercuric ion is added for part a) and from (2) hydroboration–oxidation:
a. 1-butyne 

검증된 단계별 안내
1
Step 1: Understand the reaction types. Acid-catalyzed hydration of alkynes involves the addition of water in the presence of an acid (H₂SO₄) and mercuric ion (Hg²⁺) as a catalyst. This reaction follows Markovnikov's rule and forms an enol intermediate, which tautomerizes to a ketone. Hydroboration-oxidation, on the other hand, involves the addition of BH₃ (or a borane derivative) followed by oxidation with H₂O₂/NaOH, leading to an anti-Markovnikov product, typically an aldehyde or ketone.
Step 2: For acid-catalyzed hydration of 1-butyne, identify the Markovnikov product. The water molecule adds across the triple bond such that the hydroxyl group (-OH) attaches to the more substituted carbon (C-2). This forms an enol intermediate, which undergoes keto-enol tautomerization to yield 2-butanone (a ketone).
Step 3: For hydroboration-oxidation of 1-butyne, identify the anti-Markovnikov product. The boron atom from BH₃ adds to the less substituted carbon (C-1) of the triple bond. After oxidation with H₂O₂/NaOH, the resulting product is an aldehyde, specifically butanal.
Step 4: Draw the structures of the intermediates and final products. For acid-catalyzed hydration, show the enol intermediate (CH₃-CH(OH)-CH=CH₂) and the final ketone product (CH₃-CO-CH₂-CH₃). For hydroboration-oxidation, show the intermediate organoborane and the final aldehyde product (CH₃-CH₂-CH₂-CHO).
Step 5: Verify the regioselectivity and stereochemistry of the products. Ensure that the acid-catalyzed hydration follows Markovnikov's rule and that the hydroboration-oxidation follows anti-Markovnikov's rule. Confirm that the products are consistent with the reaction mechanisms.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
4m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Acid-Catalyzed Hydration of Alkynes

In acid-catalyzed hydration, alkynes react with water in the presence of an acid catalyst, typically forming an enol that quickly tautomerizes to a ketone. For terminal alkynes like 1-butyne, the addition of water leads to the formation of a carbonyl compound, with the mercuric ion facilitating the reaction by stabilizing the carbocation intermediate.
추천 영상:
09:11
Alkyne Hydration

Hydroboration-Oxidation

Hydroboration-oxidation is a two-step reaction where an alkene or alkyne first reacts with diborane (B2H6) to form an organoborane intermediate, followed by oxidation with hydrogen peroxide (H2O2) in a basic solution. This method results in the anti-Markovnikov addition of water, leading to the formation of alcohols, which can be further converted to carbonyl compounds.
추천 영상:
06:38
General properties of hydroboration-oxidation.

Tautomerization

Tautomerization is a chemical reaction that involves the rearrangement of bonds within a compound, typically resulting in the interconversion between an enol and a carbonyl compound (keto form). In the context of alkynes, after acid-catalyzed hydration, the enol form is often unstable and quickly converts to the more stable ketone, which is crucial for understanding the final products of the reaction.
추천 영상:
05:11
Tautomerization Mechanisms
관련 실천
교과서 질문

Describe the alkyne you should start with and the reagents you should use if you want to synthesize

b. cis-2-butene.

1285
views
교과서 질문

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

1264
views
교과서 질문

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

1213
views
교과서 질문

Describe the alkyne you should start with and the reagents you should use if you want to synthesize

a. pentane.

1146
views
교과서 질문

Which alkyne should be used for the synthesis of each of the following ketones?

a.

b.

877
views
교과서 질문

Which alkyne should be used for the synthesis of each of the following ketones?

c.

829
views