Question

Predict the \(\beta\)-elimination product(s) formed when each chloroalkane is treated with sodium ethoxide in ethanol. If two or more products might be formed, predict which is the major product.

Short answer

Question: Predict the major product formed when a given chloroalkane is treated with sodium ethoxide in ethanol. Answer: To predict the major product, follow the steps below: 1. Identify the substrate (chloroalkane) and leaving group (chloride ion). 2. Recognize that sodium ethoxide acts as a strong base, making the reaction likely to proceed by the E2 mechanism. 3. Identify the β-hydrogen(s) on the β-carbon(s) adjacent to the carbon attached to the leaving group. 4. Determine the potential elimination products by forming alkene(s) where the β-hydrogen and leaving group get eliminated. 5. Use Saytzeff's Rule to determine the major product, which will be the more stable alkene with the greater number of substituents on the double bond.

Step-by-step solution

Identify the substrate and leaving group

In this exercise, the chloroalkane acts as the substrate, and the chloride ion is the leaving group.

Identify the base and mechanism

Sodium ethoxide (NaOEt) acts as the base in this reaction, and ethanol as the solvent. Since ethoxide is a strong base, the reaction most likely proceeds by the E2 mechanism.

Identify the β-hydrogen

Identify the β-carbon(s) adjacent to the carbon attached to the leaving group (chloride). There should be hydrogen atoms on the β-carbon(s) which will be eliminated during the reaction.

Determine the potential elimination products

For each β-hydrogen, form an alkene where the β-hydrogen and the leaving group (chloride) gets eliminated.

Determine the major product using Saytzeff's Rule

According to Saytzeff's Rule, the major product will be the more stable alkene (or alkenes in case of equal stability), which is the one with the greater number of substituents on the double bond. Considering the above steps, for any given chloroalkane, the major product (and other possible products, if any) can be predicted when treated with sodium ethoxide in ethanol.