Chapter 20: Q19P (page 1038)

Suggest how you would convert trans-4-methylcyclohexanol to
(a) trans-1-chloro-4-methylcyclohexane.
(b) cis-1-chloro-4-methylcyclohexane.

Short Answer

Expert verified

(a)

(b)

Step by step solution

Step 1: Chemical Reaction of Alcohols

Alcohol, while showing their chemical change, act as a “versatile” organic compound. It can act both as a nucleophile (Nu^- ) as well as an electrophile(E⁺ ).

The chemical reaction of Alcohols are of two types:

Reaction involving cleavage of O-H bond
Reaction involving cleavage of C-OH bond

Conversion of reactant trans-4-methyl cyclohexanol to given products

trans-4-methyl cyclohexanol, when reacting withThionyl chloride (SOCl2), is the best reagent for converting an alcohol to an alkyl chloride and as the by-products (gaseous SO2 and HCl) leave the reaction mixture and ensure there can be no reverse reaction. Thus the trans-4-methyl cyclohexanol has been converted to trans-1-chloro-4-methylcyclohexane when reacted with Thionyl chloride (SOCl2).

Conversion of trans-4-methyl cyclohexanol to trans-1-chloro-4-methylcyclohexane

b. trans-4-methyl cyclohexanol, when reacted with tosyl chloride (TsCl) in the presence of pyridine, forms the tosylate ester. Tosylate ester reacts with sodium chloride (NaCl) shows S_N2 displacement of tosylate ion forms the tosylate ester with inversion of configuration leading to the formation of cis 1-chloro-4-methylcyclohexane.