What product do you predict from the reaction of \(\mathrm{SCl}_{2}\) with benzene in the presence of \(\mathrm{AlCl}_{3}\) ? What product results if diphenyl ether is treated with \(\mathrm{SCl}_{2}\) and \(\mathrm{AlCl}_{3}\) ?

Benzene is known for its remarkable stability due to its aromatic nature, which is characterized by a ring of six carbon atoms bonded in a planar hexagonal arrangement with resonance-stabilized bonding. When it comes to its reactions, benzene typically undergoes what is known as electrophilic aromatic substitution (EAS), a common reaction mechanism that preserves the aromaticity of the benzene ring after the reaction.

During a typical EAS, benzene reacts with an electrophile, which is an electron-deficient species eager to accept electrons. The process involves the temporary disruption of aromaticity as the electrophile forms a bond with a carbon on the benzene ring, forming a non-aromatic intermediate known as a sigma complex or arenium ion. The original aromaticity is restored when a hydrogen is abstracted, usually with the help of a Lewis acid catalyst like AlCl3.

Electrophilic aromatic substitution is a multistep pathway, crucial for modifying benzene and its derivatives. The general steps for EAS are:

1. Generation of an electrophile.
2. Formation of the arenium ion intermediate.
3. Deprotonation to regenerate aromaticity.
4. Restoration of the catalyst, if applicable.

For example, in the reaction of benzene with SCl2 in the presence of a Lewis acid like AlCl3, an electrophilic sulfur species is formed that attacks the benzene, initially disrupting its delocalized electronic structure. Subsequent steps lead to the reformation of the aromatic system and the production of chlorobenzene sulfenyl chloride. This type of reaction is essential in organic chemistry, as it forms the basis for many synthetic transformations used to prepare a wide array of complex molecules.

Organosulfur compounds are a class of organic molecules that contain sulfur atoms. These compounds have diverse applications, from pharmaceuticals to materials science. The sulfenyl chlorides, which are formed as products in the reactions described in the textbook exercises, are a subset of organosulfur compounds.

In Friedel-Crafts reactions involving organosulfur compounds, like the reaction of SCl2 with benzene or diphenyl ether, unique electrophiles are generated. The sulfur atom in these reactions acts as an electrophile due to its ability to accept electrons, resulting in aromatic substitution. Organosulfur compounds are particularly interesting in organic synthesis because they can act as intermediates, which can be further transformed into more complex structures, increasing the molecular diversity achievable by chemists.