Textbook Question
Predict the product for each of the following reactions.
(a)
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12. Alcohols, Ethers, Epoxides and Thiols
Leaving Group Conversions - Sulfonyl Chlorides
Problem 22
Textbook Question
The sulfur atom in toluene sulfonyl chloride (TsCl) is strongly electrophilic. Why?
Verified step by step guidance1
Examine the structure of toluene sulfonyl chloride (TsCl). The sulfur atom is bonded to two oxygen atoms, one chlorine atom, and a benzene ring through a sulfonyl group.
Recognize that the sulfur atom in TsCl is part of a sulfonyl group, which is characterized by the presence of two double-bonded oxygen atoms. These oxygen atoms are highly electronegative.
Understand that the electronegative oxygen atoms withdraw electron density from the sulfur atom through resonance and inductive effects, making the sulfur atom electron-deficient.
Consider the role of the chlorine atom, which is also electronegative and can further withdraw electron density from the sulfur atom through inductive effects, enhancing the electrophilicity of the sulfur.
Conclude that the combination of electron-withdrawing effects from the oxygen and chlorine atoms makes the sulfur atom in TsCl a strong electrophile, as it seeks to accept electrons to alleviate its electron deficiency.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilicity
Electrophilicity refers to the tendency of a species to accept electrons. Electrophiles are typically positively charged or neutral species with an incomplete octet, making them reactive towards nucleophiles. In the case of toluene sulfonyl chloride, the sulfur atom is electrophilic due to its ability to attract electron pairs from nucleophiles, facilitating chemical reactions.
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Sulfonyl Chloride Structure
Sulfonyl chlorides, like toluene sulfonyl chloride, contain a sulfonyl group (SO2) bonded to a chlorine atom. The sulfur atom in this group is bonded to two oxygen atoms via double bonds and to a chlorine atom, creating a highly polarized structure. This polarization enhances the electrophilic character of sulfur, making it more susceptible to nucleophilic attack.
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Resonance Stabilization
Resonance stabilization occurs when a molecule can be represented by multiple valid Lewis structures, leading to a delocalization of electrons. In toluene sulfonyl chloride, the resonance between the sulfur and oxygen atoms allows for the distribution of positive charge, increasing the electrophilicity of the sulfur atom. This delocalization makes the sulfur more reactive towards nucleophiles.
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