Question

Predict the products of the following reactions:

(a)

(b)

(c)

(d)

Short answer

(a)

Products of reaction (a)

(b)

Product of reaction (b)

(c)

Product of reaction (c)

(d)

Product of reaction (d)

Step-by-step solution

Ethers and thiols

Organic compounds that contain a C-O-C bond are called ethers. These compounds are named by the number of carbon atoms on each side of the oxygen atom. If the number of carbon atoms on each side of the oxygen atom is the same, then the ether is considered symmetrical.

Thiols are compounds that contain a sulfur atom directly attached to the carbon atom. They are the sulfur analogs of alcohols. These compounds can capture mercury and therefore are called mercaptans.

Reactivity of oxygen-containing and sulfur-containing compounds

In the ether, the two alky chains on oxygen are electron-donating. Due to this, the oxygen atom becomes electron-rich and therefore can donate its lone pair easily. This makes ether oxygen nucleophilic. It can form a coordinate bond with electron deficient atoms and accept a proton to form an O-H bond.

The thiols are more acidic than alcohols as the electronegativity of sulfur is lower than that of oxygen. Due to the low electronegativity, sulfur can easily donate its lone pair and therefore, thiols are more nucleophilic than alcohols.

Products of the given reactions

(a) In this reaction, the nucleophilic oxygen atom of the ether captures the proton from hydrogen bromide and produces a positive charge. The bromide ion formed during the reaction forms a bond with the alkyl group to form alkyl bromide and alcohol.

The reaction can be given as:

Reaction (a)

(b) In this reaction, the lone pair on the sulfur atom attacks the electrophilic carbon atom removing the bromide ion and forming a C-S bond. The sulfur atom obtains a positive charge. On hydrolysis in the presence of a base, the adduct removes the ammonia groups to form a thiol.

The reaction can be given as:

Reaction (b)

(c) In this reaction, The thiol forms a thiolate ion in the presence of a base which reacts with the bromine to form an S-Br bond. This compound reacts with another thiolate ion to form a disulfide.

The reaction can be given as:

Reaction (c)

(d) The given reaction is the oxidation of thioethers producing sulfoxides. The reaction is carried out using peroxides in the presence of a base. Thioethers are oxidized at room temperature.

The reaction can be given as:

Reaction (d)