Give the structures of the intermediates and products V through Z.

Verified step by step guidance

1. Step 1: Analyze the first reaction in the sequence. Cyclopentanol reacts with PBr₃, which is a reagent used to convert alcohols into alkyl bromides. The hydroxyl group (-OH) of cyclopentanol is replaced by a bromine atom, forming cyclopentyl bromide (W).
2. Step 2: In the second reaction, cyclopentyl bromide (W) reacts with magnesium in ether. This reaction forms a Grignard reagent, cyclopentyl magnesium bromide (X). Grignard reagents are highly reactive organometallic compounds used in nucleophilic addition reactions.
3. Step 3: Cyclopentanol undergoes oxidation with Na₂Cr₂O₇ in H₂SO₄ to form cyclopentanone (V). This is a typical oxidation reaction where a secondary alcohol is converted into a ketone.
4. Step 4: The Grignard reagent (X) reacts with cyclopentanone (V) in the presence of H₃O⁺. This reaction forms a tertiary alcohol (Y) through nucleophilic addition of the Grignard reagent to the ketone group of cyclopentanone.
5. Step 5: The tertiary alcohol (Y) reacts with acetyl chloride (CH₃COCl). This reaction involves acylation, where the hydroxyl group of the alcohol is replaced by an acetyl group, forming an ester (Z).

Key Concepts

Reactions of Alcohols

Alcohols can undergo various reactions, including conversion to alkyl halides. In this case, cyclopentanol is treated with phosphorus tribromide (PBr3), which facilitates the substitution of the hydroxyl group (-OH) with a bromine atom, forming an alkyl bromide. This step is crucial for generating the intermediate W.

Grignard Reagents

Grignard reagents are organomagnesium compounds that react with electrophiles to form new carbon-carbon bonds. In the reaction sequence, the alkyl bromide formed from cyclopentanol reacts with magnesium in ether to produce a Grignard reagent (X). This reagent is highly reactive and can further react with carbonyl compounds in subsequent steps.

Oxidation and Functional Group Transformations

Oxidation reactions involve the increase of oxidation state, often resulting in the formation of carbonyl compounds. In this sequence, the Grignard reagent (X) reacts with a carbonyl compound to form an alcohol (Y), which can then be oxidized using sodium dichromate (Na2Cr2O7) in sulfuric acid (H2SO4) to yield a ketone (Z). Understanding these transformations is essential for predicting the structures of intermediates and products.