Chapter 8.9, Problem 27CC

(a)

Interpretation Introduction

Interpretation:

Carbocation intermediate should be drawn for all the given substrates during E1 elimination process.

Concept introduction:

• Elimination reaction: In elimination reaction, two substituents are removed from the substrate to give the product in presence of base. Elimination reactions are two types, E1 and E2.
• E1 reaction: elimination follows stepwise mechanism. Rate of the reaction depends only on substrate concentration because rate-determining step is carbocation formation step.

  $\text{r}\propto \text{[substrate]}$

• E2 reaction: elimination follows concerted pathway of mechanism. Rate of the reaction depends on both substrates as well as reagent concentration.

  $\text{r}\propto \text{[substrate]}\left[\text{base}\right]$

• Elimination of compound in presence of bulky base leads to less substituted alkene, in presence of strong base (not bulky) leads to more substituted alkene.

(b)

Interpretation Introduction

Interpretation:

Carbocation intermediate should be drawn for all the given substrates during E1 elimination process.

Concept introduction:

• Elimination reaction: In elimination reaction, two substituents are removed from the substrate to give the product in presence of base. Elimination reactions are two types, E1 and E2.
• E1 reaction: elimination follows stepwise mechanism. Rate of the reaction depends only on substrate concentration because rate-determining step is carbocation formation step.

  $\text{r}\propto \text{[substrate]}$

• E2 reaction: elimination follows concerted pathway of mechanism. Rate of the reaction depends on both substrates as well as reagent concentration.

  $\text{r}\propto \text{[substrate]}\left[\text{base}\right]$

• Elimination of compound in presence of bulky base leads to less substituted alkene, in presence of strong base (not bulky) leads to more substituted alkene.

(c)

Interpretation Introduction

Interpretation:

Carbocation intermediate should be drawn for all the given substrates during E1 elimination process.

Concept introduction:

• Elimination reaction: In elimination reaction, two substituents are removed from the substrate to give the product in presence of base. Elimination reactions are two types, E1 and E2.
• E1 reaction: elimination follows stepwise mechanism. Rate of the reaction depends only on substrate concentration because rate-determining step is carbocation formation step.

  $\text{r}\propto \text{[substrate]}$

• E2 reaction: elimination follows concerted pathway of mechanism. Rate of the reaction depends on both substrates as well as reagent concentration.

  $\text{r}\propto \text{[substrate]}\left[\text{base}\right]$

• Elimination of compound in presence of bulky base leads to less substituted alkene, in presence of strong base (not bulky) leads to more substituted alkene.

(d)

Interpretation Introduction

Interpretation:

Carbocation intermediate should be drawn for all the given substrates during E1 elimination process.

Concept introduction:

• Elimination reaction: In elimination reaction, two substituents are removed from the substrate to give the product in presence of base. Elimination reactions are two types, E1 and E2.
• E1 reaction: elimination follows stepwise mechanism. Rate of the reaction depends only on substrate concentration because rate-determining step is carbocation formation step.

  $\text{r}\propto \text{[substrate]}$

• E2 reaction: elimination follows concerted pathway of mechanism. Rate of the reaction depends on both substrates as well as reagent concentration.

  $\text{r}\propto \text{[substrate]}\left[\text{base}\right]$

• Elimination of compound in presence of bulky base leads to less substituted alkene, in presence of strong base (not bulky) leads to more substituted alkene.