Question

1-Phenyl-2-butanol is used in perfumery. Show how to synthesize this alcohol from bromobenzene, 1-butene, and any necessary inorganic reagents. Figure can`t copy

Short answer

Question: Synthesize 1-phenyl-2-butanol starting from bromobenzene, 1-butene, and any necessary inorganic reagents. Answer: To synthesize 1-phenyl-2-butanol, follow these steps: 1. Form a Grignard reagent (phenyl magnesium bromide) by reacting bromobenzene with magnesium in anhydrous ether. 2. Protonate 1-butene using sulfuric acid (H2SO4) to generate 2-butanol. 3. Combine the Grignard reagent (phenyl magnesium bromide) with 2-butanol. The Grignard reagent acts as a nucleophile, attacking the carbonyl group of 2-butanol, resulting in the formation of 1-phenyl-2-butanol.

Step-by-step solution

Formation of Grignard Reagent

The first step in this synthesis is to form a Grignard Reagent, which is a powerful nucleophile, from bromobenzene. To do this, perform a Grignard reaction by adding magnesium turnings to bromobenzene in anhydrous ether as a solvent. This reaction forms the phenyl magnesium bromide Grignard reagent and the general equation is as follows: \[ \mathrm{Br-C_{6}H_{5} + Mg \xrightarrow{ether} C_{6}H_{5}MgBr}\]

Protonating 1-Butene

The second step is to protonate 1-butene to generate 2-butanol, which will then be used in the next reaction. Treat 1-butene in the presence of a strong acid, such as sulfuric acid (H2SO4), to form 2-butanol. The general equation for this reaction is: \[ \mathrm{H_{2}C=CH-CH_{2}CH_{3} + H_{2}O \xrightarrow{H_{2}SO_{4}} CH_{3}CH(OH)C_{H_{2}}CH_{3}}\]

Synthesis of 1-Phenyl-2-Butanol

In the final step, combine the phenyl magnesium bromide (Grignard reagent) from step 1 with 2-butanol from step 2. The Grignard reagent acts as a nucleophile in this step, attacking the carbonyl group of 2-butanol, resulting in the formation of 1-phenyl-2-butanol: \[ \mathrm{C_{6}H_{5}MgBr + CH_{3}CH(OH)CH_{2}CH_{3} \xrightarrow{ether} C_{6}H_{5}CH(OH)CH(CH_{3})CH_{3} + MgBrOH}\] The final product, 1-phenyl-2-butanol, is now synthesized from bromobenzene, 1-butene, and the necessary inorganic reagents.