Chapter 8, Problem 8.55P

Draw the organic products formed in each reaction.

a. e. h.

b. f. i.

c. g. j.

d.

Interpretation Introduction

(a)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Primary alkyl halides can undergo substitution as well as elimination reactions, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given reaction involves primary alkyl halide and strong bulky base. Primary alkyl halides can undergo substitution as well as elimination reactions. Since, the base is strong and bulky; it undergoes elimination reaction through $\text{E2}$ pathway to yield the desired alkene.

The corresponding reaction is shown below.

Figure 1

Conclusion

The organic product formed in the given reaction is drawn in Figure 1.

Interpretation Introduction

(b)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Primary alkyl halides can undergo substitution as well as elimination reactions, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic products formed in the given reaction are shown below.

Explanation of Solution

In the given reaction, the alkyl halide is primary and ethoxide ion is a strong base. Primary alkyl halides can undergo substitution as well as elimination reactions. Since, the base is strong, and also a strong nucleophile, the given halide undergoes substitution reaction through ${\text{S}}_{\text{N}}\text{2}$ pathway as well as elimination reaction through $\text{E2}$ pathway.

The corresponding reaction is shown below.

Figure 2

Conclusion

The organic product formed in the given reaction is drawn in Figure 2.

Interpretation Introduction

(c)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: A carbon atom bonded to two halogen groups is called germinal dihalides. Geminal dihalides undergo double dehydrohalogenation reaction in the presence of excess base to form alkyne as the final product. The reaction prefers elimination pathway.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

In the given reaction, germinal dihalide is the starting material and amine base is strong, negatively charged and present in excess amount $\left(\text{2 moles}\right)$. Geminal dihalide undergo double dehydrohalogenation reaction in the presence of excess base to form alkyne as the final product. An E2 pathway is followed for this reaction.

The corresponding reaction is shown below.

Figure 3

Conclusion

The organic product formed in the given reaction is drawn in Figure 3.

Interpretation Introduction

(d)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Primary alkyl halides can also undergo substitution as well as elimination reactions, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

In the given reaction, the alkyl halide is primary and base is strong, but non-nucleophilic. Primary alkyl halides can undergo substitution as well as elimination reactions. Since, the base is strong and non-nucleophilic, it undergoes elimination reaction through E2 pathway.

The corresponding reaction is shown below.

Figure 4

Conclusion

The organic product formed in the given reaction is drawn in Figure 4.

Interpretation Introduction

(e)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Secondary alkyl halides can undergo substitution as well as elimination reactions, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

In the given reaction, the alkyl halide is secondary and base is a strong, negatively charged bulky base. Secondary alkyl halides can undergo substitution as well as elimination reactions. Since, the base is strong and bulky it undergoes elimination reaction through E2 pathway.

The corresponding reaction is shown below.

Figure 5

Conclusion

The organic product formed in the given reaction is drawn in Figure 5.

Interpretation Introduction

(f)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Tertiary alkyl halides can undergo substitution as well as elimination reactions $\left({\text{S}}_{\text{N}}\text{1 or E1}\right)$, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given reaction involves tertiary alkyl halide, weak base that is also a weak nucleophile. These conditions make the given halide (tertiary) suitable to undergo either substitution by ${\text{S}}_{\text{N}}\text{1}$ pathway or elimination through $\text{E1}$ pathway.

The corresponding reaction is shown below.

Figure 6

Conclusion

The organic product formed in the given reaction is drawn in Figure 6.

Interpretation Introduction

(g)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: Vicinal dihalides are the compounds in which the adjacent carbon atoms possess halogen groups (one on each carbon). These dihalides yield alkynes when treated with two equivalents of sodamide ${\text{NaNH}}_2$.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given alkyl halide is vicinal dihalide.

Vicinal dihalides are the compounds in which the adjacent carbon atoms possess halogen groups (one on each carbon). These dihalides yield alkynes when treated with two equivalents of sodamide ${\text{NaNH}}_2$.

The corresponding reaction is shown below.

Figure 7

Conclusion

The organic product formed in the given reaction is drawn in Figure 7.

Interpretation Introduction

(h)

Interpretation: The organic product formed in the given reaction is to be drawn.

Vicinal dihalides are the compounds in which the adjacent carbon atoms possess halogen groups (one on each carbon). These dihalides yield alkynes when treated with two equivalents of sodamide ${\text{NaNH}}_2$.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given alkyl halide is vicinal dihalide.

Vicinal dihalides are the compounds in which the adjacent carbon atoms possess halogen groups (one on each carbon). These dihalides yield alkynes when treated with two equivalents of DMSO.

The corresponding reaction is shown below.

Figure 8

Conclusion

The organic product formed in the given reaction is drawn in Figure 8.

Interpretation Introduction

(i)

Interpretation: The dehydrohalogenation reaction of primary alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Tertiary alkyl halides can undergo substitution as well as elimination reactions $\left({\text{S}}_{\text{N}}\text{1 or E1}\right)$, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given reaction involves secondary alkyl halide and a base that is also a weak nucleophile. These conditions make the given halide (secondary) suitable to undergo either substitution by ${\text{S}}_{\text{N}}\text{1}$ pathway or elimination through $\text{E1}$ pathway.

The corresponding reaction is shown below.

Figure 9

Conclusion

The organic product formed in the given reaction is drawn in Figure 9.

Interpretation Introduction

(j)

Interpretation: The organic product formed in the given reaction is to be drawn.

Concept introduction: The dehydrohalogenation reaction of alkyl halide mostly favors $\text{E2}$ mechanism to yield alkenes. The mechanism is concentrated and takes place in single step. Secondary alkyl halides can undergo substitution as well as elimination reactions, depending upon the alkyl halide, solvent and base used.

Answer to Problem 8.55P

The organic product formed in the given reaction is,

Explanation of Solution

The given alkyl halide is tertiary. Water is a weak base. These conditions make the given halide (tertiary) suitable to undergo substitution as well as elimination reaction $\left({\text{S}}_{\text{N}}\text{1 or E1}\right)$.

The corresponding reaction is shown below.

Figure 10

Conclusion

The organic product formed in the given reaction is drawn in Figure 10.