Skip to main content
Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMullins 1st EditionCh. 12 - Substitution and Elimination: Reactions of HaloalkanesProblema 58a
Capitolo 11, Problema 58a

For each pair, choose the haloalkane that would react most quickly in an SN2 reaction.
(a)

Guida verificata passo dopo passo
1
Step 1: Recall the key factors that influence the rate of an SN2 reaction. The SN2 mechanism involves a single-step nucleophilic substitution, where the nucleophile attacks the electrophilic carbon and displaces the leaving group. The rate of SN2 reactions is highly dependent on steric hindrance around the electrophilic carbon.
Step 2: Analyze the structures of the two haloalkanes provided in the image. The first structure has a bromine atom attached to a secondary carbon (a carbon bonded to two other carbons), while the second structure has a bromine atom attached to a primary carbon (a carbon bonded to only one other carbon).
Step 3: Understand that steric hindrance is lower for primary carbons compared to secondary carbons. In SN2 reactions, the nucleophile needs unhindered access to the electrophilic carbon to attack effectively. Therefore, primary haloalkanes generally react faster in SN2 reactions than secondary haloalkanes.
Step 4: Compare the two haloalkanes. The haloalkane with bromine attached to the primary carbon (on the right) will experience less steric hindrance, making it more reactive in an SN2 reaction compared to the haloalkane with bromine attached to the secondary carbon (on the left).
Step 5: Conclude that the haloalkane with bromine attached to the primary carbon (on the right) would react most quickly in an SN2 reaction due to reduced steric hindrance and better accessibility for the nucleophile.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Sₙ2 Reaction Mechanism

The Sₙ2 (substitution nucleophilic bimolecular) reaction is a type of nucleophilic substitution where the nucleophile attacks the electrophile simultaneously as the leaving group departs. This concerted mechanism results in the inversion of configuration at the carbon center. The rate of the Sₙ2 reaction depends on steric hindrance and the strength of the nucleophile, making primary haloalkanes more reactive than secondary or tertiary ones.
Video consigliato:
02:16
Heck Reaction Mechanism

Steric Hindrance

Steric hindrance refers to the prevention of chemical reactions due to the spatial arrangement of atoms within a molecule. In the context of Sₙ2 reactions, bulky groups around the carbon atom can impede the approach of the nucleophile, slowing down the reaction. Therefore, haloalkanes with less steric hindrance, such as primary haloalkanes, will generally react more quickly than those with greater steric hindrance, like tertiary haloalkanes.
Video consigliato:
02:53
Understanding steric effects.

Leaving Group Ability

The ability of a leaving group to depart from a molecule is crucial in determining the rate of nucleophilic substitution reactions. Good leaving groups, such as iodide or bromide, stabilize the negative charge after leaving, facilitating the reaction. In Sₙ2 reactions, the presence of a better leaving group can significantly enhance the reaction rate, making it an important factor to consider when comparing different haloalkanes.
Video consigliato:
03:06
How to use the factors affecting acidity to predict leaving group ability.
Pratica correlata
Domanda del libro di testo

For each pair, choose the nucleophile that would react most quickly in an SN2 reaction (assume H2O is the solvent).

(c)

1112
views
Domanda del libro di testo

For each pair, choose the haloalkane that would react most quickly in an SN2 reaction.

(d)

1236
views
Domanda del libro di testo

For each pair, choose the nucleophile that would react most quickly in an SN2 reaction (assume H2O is the solvent).

(b)

961
views
Domanda del libro di testo

For each pair, choose the nucleophile that would react most quickly in an SN2 reaction (assume H2O is the solvent).

(d)

997
views
Domanda del libro di testo

For each pair, choose the haloalkane that would react most quickly in an SN2 reaction.

(b)

1140
views
Domanda del libro di testo

For each pair, choose the haloalkane that would react most quickly in an SN2 reaction.

(c)

888
views