Question

Show how to convert cyclopentanone to these compounds. In addition to cyclopentanone, use any other organic or inorganic reagents as necessary.

Short answer

Question: Describe the general process for converting cyclopentanone to 1-methylcyclopentanol using a Grignard reaction. Answer: To convert cyclopentanone to 1-methylcyclopentanol using a Grignard reaction, follow these steps: 1. Prepare the Grignard reagent by mixing methyl iodide (CH3I) with magnesium (Mg) in an ether. 2. Add the Grignard reagent to cyclopentanone. 3. The reaction creates a new C-C bond and an alkoxide intermediate, which forms 1-methylcyclopentanol after quenching it with water.

Step-by-step solution

1. Grignard Reaction

In a Grignard reaction, a carbon nucleophile is generated using an alkyl halide and magnesium in ether, forming a Grignard reagent. Cyclopentanone can then be reacted with the Grignard reagent to form a new carbon-carbon bond. An example is the conversion of cyclopentanone to 1-methylcyclopentanol: 1. Prepare the Grignard reagent by mixing methyl iodide (CH3I) with magnesium (Mg) in an ether. 2. Add the Grignard reagent to cyclopentanone (\chemfig{O=[:30]-[:330]*5(----)}). 3. The reaction creates a new C-C bond and an alkoxide intermediate, leading to 1-methylcyclopentanol (\chemfig{*5(----(-O-MgBr)-)}), after quenching it with water.

2. Reduction Reaction

Cyclopentanone can be reduced to cyclopentanol using hydride reduction agents, such as sodium borohydride (NaBH4) or lithium aluminum hydride (LiAlH4). The carbonyl group in cyclopentanone is converted into a hydroxyl group. Follow these steps to achieve a reduction reaction: 1. Add a hydride reduction agent such as sodium borohydride (NaBH4) to a solution containing cyclopentanone (\chemfig{O=[:30]-[:330]*5(----)}). 2. The reaction leads to the reduction of the carbonyl group, forming an alkoxide intermediate. 3. Quench the reaction with water to give cyclopentanol (\chemfig{[:0]*5(-----O)}).

3. Baeyer-Villiger Oxidation

In the Baeyer-Villiger oxidation, the carbonyl group in cyclopentanone is oxidized by a peroxyacid, such as meta-chloroperoxybenzoic acid (MCPBA), leading to the formation of an ester. In case of cyclopentanone, the oxidation results in the formation of 1-cyclopentylmethanoate. Here's a step-by-step process for this reaction: 1. Mix cyclopentanone (\chemfig{O=[:30]-[:330]*5(----)}) with a peroxyacid like meta-chloroperoxybenzoic acid (MCPBA) in a solvent, such as dichloromethane (DCM). 2. The reaction results in an insertion of an oxygen atom in the α-position of the carbonyl group, giving a cyclic ester called 1-cyclopentylmethanoate (\chemfig{-[:60]O=*6(-(-(=[*:60]O))----)}). These are three examples of reactions involving cyclopentanone. To design a synthetic pathway to a specific target compound, the functional groups present in the target molecule should be analyzed, and the available transformations should be incorporated accordingly.