Show how you would accomplish the following syntheses efficiently and in good yield. You may use any necessary reagents.
(e)

Verified step by step guidance

1. Step 1: Analyze the transformation. The starting material is a cyclopentanone with an aldehyde group at the beta position. The product introduces an ethyl group at the alpha position of the ketone, forming an α,β-unsaturated aldehyde.
2. Step 2: Perform an α-alkylation reaction. Treat the cyclopentanone with a strong base, such as LDA (lithium diisopropylamide), to generate the enolate ion. This enolate is nucleophilic at the alpha position.
3. Step 3: Introduce the ethyl group. React the enolate with ethyl bromide (CH3CH2Br) or ethyl iodide (CH3CH2I) in an SN2 reaction to alkylate the alpha position of the ketone.
4. Step 4: Perform an aldol condensation. Treat the α-ethyl cyclopentanone with a base, such as NaOH or KOH, to form an enolate at the alpha position. This enolate will attack the aldehyde group intramolecularly, forming a β-hydroxy ketone intermediate.
5. Step 5: Dehydrate the β-hydroxy ketone. Heat the intermediate under acidic or basic conditions to eliminate water and form the α,β-unsaturated aldehyde product.

Key Concepts

Reaction Mechanisms

Understanding reaction mechanisms is crucial in organic chemistry as it describes the step-by-step process by which reactants transform into products. This includes identifying intermediates, transition states, and the role of catalysts. A clear grasp of mechanisms helps predict the outcome of reactions and optimize conditions for better yields.

Reagents and Conditions

The choice of reagents and reaction conditions significantly influences the efficiency and yield of a synthesis. Different reagents can provide specific functional groups or facilitate particular reaction pathways. Additionally, factors such as temperature, pressure, and solvent can affect reaction rates and selectivity, making it essential to select the right conditions for the desired outcome.

Yield and Efficiency

Yield refers to the amount of product obtained from a reaction compared to the theoretical maximum, while efficiency encompasses both yield and the time and resources used. High yield and efficiency are desirable in synthetic chemistry, as they indicate a successful reaction with minimal waste. Understanding how to maximize these factors is key to effective synthesis.