Question

Draw the structures of the major monohalo products in each of the following reactions:

Hint:

Thionyl chloride (SOCl\textsubscript{2}) is commonly used to convert alcohols into alkyl chlorides.

Answer 1

(a) Conversion of Alcohol to Alkyl Chloride using Thionyl Chloride

A hydroxymethyl group (\(-{CH2OH}\)) is converted to its corresponding chloro derivative by reaction with thionyl chloride (\({SOCl2}\)).

The reaction yields benzyl chloride, proceeding through the conversion of the hydroxyl group into a good leaving group, followed by chlorine substitution.

Product structure:

\[ {C6H5CH2Cl} \]

Quick Tip:
Thionyl chloride (\({SOCl2}\)) efficiently converts alcohols to alkyl chlorides.

---

(b) Anti-Markovnikov Addition of HBr to Styrene

Styrene (\({C6H5CH=CH2}\)) reacts with \({HBr}\) in the presence of a peroxide.

The peroxide effect (Kharasch effect) initiates a free radical mechanism, leading to the anti-Markovnikov product. Consequently, the bromine atom attaches to the less substituted carbon of the double bond.

Major Product: 1-bromo-2-phenylethane

\[ {C6H5CH2CH2Br} \]

This is a characteristic example of free radical addition to alkenes, influenced by peroxides.