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Ch.9 - Alkynes
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728당신이 사용하는 게 아니라요?교과서 변경
9장, 문제 37g,h,i

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

검증된 단계별 안내
1
Step 1: For pentanal (CH3CH2CH2CH2CHO), start with acetylene (C2H2). Perform a hydroboration-oxidation reaction to convert acetylene into an aldehyde. Use reagents such as BH3 (borane) followed by H2O2/NaOH to form an aldehyde with two carbons (ethanal, CH3CHO).
Step 2: Extend the carbon chain of ethanal to five carbons. Use a Grignard reaction by reacting ethanal with a Grignard reagent (e.g., CH3CH2CH2MgBr) followed by acidic workup to form a secondary alcohol. Then, oxidize the alcohol to the aldehyde (pentanal) using PCC (pyridinium chlorochromate).
Step 3: For pentan-2-one (CH3-CO-CH2CH2CH3), start with acetylene and perform a hydration reaction using H2SO4 and HgSO4 to form acetone (CH3-CO-CH3).
Step 4: Extend the carbon chain of acetone to five carbons. Use a Grignard reaction by reacting acetone with CH3CH2MgBr followed by acidic workup to form a tertiary alcohol. Oxidize the tertiary alcohol to the ketone (pentan-2-one) using PCC or another mild oxidizing agent.
Step 5: For (±) 3,4-dibromohexane, start with acetylene and perform a series of alkylation reactions using alkyl halides (e.g., CH3CH2Br) to extend the carbon chain to six carbons. Then, perform a bromination reaction using Br2 in CCl4 to add bromine atoms to the 3 and 4 positions of the hexane chain, ensuring the formation of the racemic mixture (±).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
18m

주요 개념

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

Acetylene as a Building Block

Acetylene (C2H2) is a simple alkyne that serves as a versatile building block in organic synthesis. It can undergo various reactions, such as addition reactions with electrophiles, to form longer carbon chains. Understanding how to manipulate acetylene through reactions like hydrohalogenation or alkylation is crucial for synthesizing more complex molecules, including those with longer carbon chains.
추천 영상:
16:59
Building a molecular sentence

Carbon Chain Elongation

Carbon chain elongation involves increasing the number of carbon atoms in a molecule through reactions such as nucleophilic substitution or coupling reactions. This concept is essential for synthesizing compounds like pentanal and pentan-2-one, where specific carbon skeletons must be constructed. Mastery of techniques like the Grignard reaction or the use of organolithium reagents can facilitate this process.
추천 영상:
04:25
Name the longest carbon chain

Functional Group Transformation

Functional group transformation refers to the process of converting one functional group into another, which is vital for achieving the desired properties in organic compounds. For example, converting an alcohol to a carbonyl group or introducing halogens into a hydrocarbon chain is often necessary in synthesis. Understanding the reactivity and compatibility of different functional groups allows chemists to design effective synthetic routes for compounds like 3,4-dibromohexane.
추천 영상:
02:36
Identifying Functional Groups