Chapter 10: Q14P (page 513)

Question: Show two ways you could synthesize each of the following secondary alcohols by adding an appropriate Grignard reagent to an aldehyde.
a.
b.
c.

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Step by step solution

Secondary alcohols by Grignard reagents

Secondary alcohols ( alcohols) are formed when the Grignard reagent (with any of three halides- Cl, Br, I) is added to aldehydes except for formaldehyde.It takes place in the presence of a solvent (like ether), and the other step is the addition of H₃O⁺ .

Formation of secondary alcohol in (a)

Grignard reagent ( ${CH}_{3} {- CH}_{2} - CH ({CH}_{3}) {- CH}_{2} MgCl$ ) and aldehyde ( ${CH}_{3} CHO$ ) are used in the first method. In the second method, the alkyl groups of Grignard reagent and aldehyde are interchanged

Formation of secondary alcohol in (b)

b. Grignard reagent ( $C_{6} H_{5} MgBr$ ) and aldehyde ( ${CH}_{3} {CH}_{2} CHO$ ) are used in the first method. In the second method, the alkyl groups of Grignard reagent and aldehyde are interchanged.

Synthesis of secondary alcohol

Formation of secondary alcohol in (c)

c. Grignard reagent ( ${CH}_{2} {= CHCH}_{2} MgCl$ ) and aldehyde ( $C_{6} H_{11} CHO$ ) are used in the first method. In the second method, the alkyl groups of Grignard reagent and aldehyde are interchanged.