Skip to main content
Ch.6 - Alkyl Halides; Nucleophilic Substitution
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Wade 9th EditionCh.6 - Alkyl Halides; Nucleophilic Substitution문제 23a,b
6장, 문제 23a,b

Choose the member of each pair that will react faster by the SN1 mechanism.
a. 1-bromopropane or 2-bromopropane
b. 2-bromo-2-methylbutane or 2-bromo-3-methylbutane

검증된 단계별 안내
1
Step 1: Recall the key factors that influence the SN1 mechanism. The SN1 reaction proceeds via a two-step mechanism: (1) formation of a carbocation intermediate and (2) nucleophilic attack on the carbocation. The rate-determining step is the formation of the carbocation, so the stability of the carbocation is the most important factor. More stable carbocations form faster, leading to a faster SN1 reaction.
Step 2: Analyze part (a): Compare 1-bromopropane and 2-bromopropane. When the leaving group (bromine) departs, 1-bromopropane would form a primary carbocation, while 2-bromopropane would form a secondary carbocation. Secondary carbocations are more stable than primary carbocations due to inductive effects and hyperconjugation, so 2-bromopropane will react faster via the SN1 mechanism.
Step 3: Analyze part (b): Compare 2-bromo-2-methylbutane and 2-bromo-3-methylbutane. When the leaving group departs, 2-bromo-2-methylbutane would form a tertiary carbocation, while 2-bromo-3-methylbutane would form a secondary carbocation. Tertiary carbocations are more stable than secondary carbocations due to greater hyperconjugation and inductive effects, so 2-bromo-2-methylbutane will react faster via the SN1 mechanism.
Step 4: Consider other factors that might influence the reaction rate, such as the quality of the leaving group (bromine is a good leaving group in both cases) and the solvent (polar protic solvents favor SN1 reactions). However, in this problem, the carbocation stability is the dominant factor.
Step 5: Summarize the results: For part (a), 2-bromopropane reacts faster via the SN1 mechanism. For part (b), 2-bromo-2-methylbutane reacts faster via the SN1 mechanism. This conclusion is based on the relative stabilities of the carbocations formed in each case.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
3m

주요 개념

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

SN1 Mechanism

The SN1 mechanism is a type of nucleophilic substitution reaction that occurs in two steps: first, the leaving group departs, forming a carbocation intermediate, followed by the nucleophile attacking the carbocation. The rate of the reaction depends primarily on the stability of the carbocation formed. More stable carbocations, such as tertiary or resonance-stabilized ones, will lead to faster reactions.
추천 영상:
10:49
Drawing the SN1 Mechanism

Carbocation Stability

Carbocation stability is a crucial factor in determining the rate of SN1 reactions. Carbocations are classified as primary, secondary, or tertiary based on the number of alkyl groups attached to the positively charged carbon. Tertiary carbocations are the most stable due to hyperconjugation and inductive effects from surrounding alkyl groups, making them more favorable for SN1 reactions.
추천 영상:
05:58
Determining Carbocation Stability

Substituent Effects

The presence and position of substituents on the carbon chain can significantly influence the reactivity in SN1 reactions. For example, branching near the reactive center can stabilize the carbocation formed during the reaction. In the given pairs, the structure of the bromopropanes will determine which compound can form a more stable carbocation, thus reacting faster via the SN1 mechanism.
추천 영상:
가이드 코스
2:02
Directing Effects in Substituted Pyrroles, Furans, and Thiophenes Concept 1
관련 실천
교과서 질문

Propose an SN1 mechanism for the solvolysis of 3-bromo-2,3-dimethylpentane in ethanol.

2856
views
교과서 질문

Choose the member of each pair that will react faster by the SN1 mechanism.

c. n-propyl bromide or allyl bromide

d. 1-bromo-2,2-dimethylpropane or 2-bromopropane

1142
views
교과서 질문

Draw a perspective structure or a Fischer projection for the products of the following SN2 reactions.

(e)

1446
views
교과서 질문

Draw a perspective structure or a Fischer projection for the products of the following SN2 reactions.

(f)

959
views
교과서 질문

3-Bromocyclohexene is a secondary halide. It undergoes SN1 substitution about as fast as most tertiary halides. Use resonance structures to explain this enhanced reactivity.

2000
views
교과서 질문

Choose the member of each pair that will react faster by the SN1 mechanism.

e. 2-iodo-2-methylbutane or tert-butyl chloride

f. 2-bromo-2-methylbutane or ethyl iodide

1114
views