8. Elimination Reactions

SN1 SN2 E1 E2 Chart (Big Daddy Flowchart) Practice Problems

8. Elimination Reactions

SN1 SN2 E1 E2 Chart (Big Daddy Flowchart) - Online Tutor, Practice Problems & Exam Prep

SN1 SN2 E1 E2 Chart (Big Daddy Flowchart) Practice Problems

98 problems

1PRACTICE PROBLEM

Consider the following reactants,

What kind of elimination reaction is anticipated to take place with this condition?

2PRACTICE PROBLEM

Consider the given reactants,

What kind of elimination reaction is expected to happen with this condition?

3PRACTICE PROBLEM

Determine if the following reaction is E1 or E2 and draw its mechanism.

4PRACTICE PROBLEM

When stereochemistry is considered, what is the product of the following elimination reaction?

5PRACTICE PROBLEM

Consider the reactions below:

Which reaction, S_N2 or E2, would occur at a higher temperature?

6PRACTICE PROBLEM

Which reaction condition favors elimination over substitution?

7PRACTICE PROBLEM

Which of the alkyl halides would undergo an S_N1 or E1 reaction faster?

8PRACTICE PROBLEM

Does the following reaction undergo a E2, E1, S_N2 or S_N1 mechanism?

9PRACTICE PROBLEM

a. Draw the major products for each of the following reactions.

b. Determine whether each of these reactions follows an E2 or an E1 mechanism.

10PRACTICE PROBLEM

Draw the major products for the given reaction. Show stereochemistry where applicable.

trans-1-bromo-2-ethylcyclohexane + CH₃O⁻

11PRACTICE PROBLEM

Draw the major products for the given reaction. Show stereochemistry where applicable.

cis-1-bromo-2-ethylcyclohexane + CH₃O⁻

12PRACTICE PROBLEM

Draw the major products expected from the elimination reaction of 4-bromo-2,4-dimethylpent-2-ene with methoxide ion.

13PRACTICE PROBLEM

Draw the major products expected from the elimination reaction shown below.

14PRACTICE PROBLEM

A small amount of a by-product is obtained during the Williamson ether synthesis of ethyl propyl ether using ethyl bromide. Draw the structure of this product.

15PRACTICE PROBLEM

A small amount of a by-product is obtained during the Williamson ether synthesis of ethyl propyl ether using propyl iodide. Draw the structure of this product.

16PRACTICE PROBLEM

Draw the three products formed in a reaction between 2-iodo-2-methylpropane and the aqueous solution of ethanol.

17PRACTICE PROBLEM

Draw the products formed in the reaction of 1-bromobutane with CH₃S⁻.

18PRACTICE PROBLEM

Draw the products formed in the reaction of 1-bromobutane with HS⁻.

19PRACTICE PROBLEM

Draw the major elimination products of the following reaction, show their stereochemistry, and indicate the major and minor stereoisomers.

trans-1-bromo-2-propylcyclohexane + concentrated CH₃O⁻

20PRACTICE PROBLEM

Draw the S_N2 and E2 products expected from the following reaction. Show stereochemistry where applicable.

(2R,3R)-2-bromo-3-methylhexane + CH₃O⁻

21PRACTICE PROBLEM

Draw the major products expected from the reaction shown below.

22PRACTICE PROBLEM

Draw the products for the below-given reaction and propose a suitable mechanism for their formation.

23PRACTICE PROBLEM

Draw the major elimination products of the following reaction, show their stereochemistry, and indicate the major and minor stereoisomers.

trans-1-bromo-3-propylcyclohexane + concentrated CH₃O⁻

24PRACTICE PROBLEM

Draw the major products of the reaction given below.

25PRACTICE PROBLEM

Predict the major products of the reaction given below.

26PRACTICE PROBLEM

a. Draw the major products of the following reaction:

cis-1-bromo-2-methylcyclopentane + CH₃O⁻

b. Are these products all optically active?

27PRACTICE PROBLEM

Predict the major elimination products of the below-given compound with a weak base and with a strong base.

28PRACTICE PROBLEM

Draw the product(s) obtained from the reaction given below.

29PRACTICE PROBLEM

Draw the product(s) obtained from the reaction shown below.

30PRACTICE PROBLEM

Draw the product(s) obtained in the following reaction of the stereoisomer of 2-bromo-1,3,5-trimethylcyclohexane.

31PRACTICE PROBLEM

When pure (3R,4R)-3-iodo-3,4-dimethylhexane is heated with sodium ethoxide in ethanol, it produces a mixture of three alkenes. Draw a mechanism that accounts for the formation of the three alkenes.

32PRACTICE PROBLEM

Determine the mechanism for the following reaction (E1, E2, S_N¹, or S_N²).

In the case of multiple products, explain which one is the major product.

33PRACTICE PROBLEM

Write a balanced chemical equation that corresponds to the following reaction. Show the expected major product in the chemical equation you write.

34PRACTICE PROBLEM

Give the products of the reaction between a benzyl bromide derivative and sodium cyanide shown below.

35PRACTICE PROBLEM

Predict the major product for the following reaction:

36PRACTICE PROBLEM

When 1-chloro-2-methylcyclopentane is heated in methanol, the reaction yields two substitution and two elimination products. Predict the products and draw plausible mechanism for the formation of each product.

37PRACTICE PROBLEM

Alkyl halides when reacting with strong bases/nucleophiles often produce a mixture of substitution and elimination products. Draw expected products for the reaction between 1-iodo-2-methylcyclohexane and sodium methoxide. Note that Zaitsev's rule applies for E2 reactions when the base is not bulky.

38PRACTICE PROBLEM

For the following reaction, predict whether the major product will be a substitution product or an elimination product. Write the major product of the reaction.

39PRACTICE PROBLEM

Determine the elimination mechanism for the following reaction (E1 or E2, ignore substitution).

Predict major and minor elimination products of this reaction.

40PRACTICE PROBLEM

Determine the mechanism for the following reaction (E1 or E2).

In the case of multiple products, explain which one is the major product.

41PRACTICE PROBLEM

Complete and balance the following reaction with the expected major product:

42PRACTICE PROBLEM

For the following reaction, write a mechanism that accounts for the formation of the shown products:

43PRACTICE PROBLEM

When pure (3R,4R)-3-iodo-3,4-dimethylhexane is heated in ethanol, it produces a mixture of two ethers and four alkenes. Draw a mechanism that accounts for the formation of the two ethers. Discuss the retention or inversion of configuration taking place in this reaction.

44PRACTICE PROBLEM

Select the correct chloroalkane and condition to produce the given alkene.

45PRACTICE PROBLEM

Identify the correct major product of the elimination reaction shown below. (Note: Pay attention to stereochemistry)

46PRACTICE PROBLEM

Give the correct major product of the elimination reaction given below. (Note: Pay attention to stereochemistry.)

47PRACTICE PROBLEM

Identify whether the given base favors an E₂ or E₁ mechanism.

48PRACTICE PROBLEM

The given reaction could undergo substitution or elimination:

What is its product? (Note: Pay attention to stereochemistry)

49PRACTICE PROBLEM

Consider the following reactants,

Predict the type of elimination reaction taking place with this condition.

50PRACTICE PROBLEM

Which reaction condition is more favorable to elimination over substitution?

51PRACTICE PROBLEM

Suggest a suitable base to produce the following alkenes from the initial alkyl halide.

52PRACTICE PROBLEM

Sketch the correct product of this reaction.

53PRACTICE PROBLEM

What is the product of the reaction given below?

54PRACTICE PROBLEM

From the two S_N2 reactions given, which is faster? Justify.

55PRACTICE PROBLEM

From these two E2 reactions, which is faster? Justify.

56PRACTICE PROBLEM

What is the final product of the reaction below?

57PRACTICE PROBLEM

For the pair of reactions shown below, which one is expected to favor elimination over substitution?

58PRACTICE PROBLEM

Draw the product of the reaction shown below.

59PRACTICE PROBLEM

Consider the reaction below:

Determine whether the reaction favors an SN1, SN2, E1, or E2 mechanism.

60PRACTICE PROBLEM

Draw the major product(s) of the reaction when the molecule below is allowed to react with the following reagents: (i) H₂O (ii) NaOH, H₂O. If there is no reaction, write “no reaction.”

61PRACTICE PROBLEM

Determine via which mechanism the following reaction will occur: S_N1, S_N2, E1, or E2.

62PRACTICE PROBLEM

Identify whether the reaction below proceeds via E1, E2, S_N1, or S_N2.

63PRACTICE PROBLEM

Determine which reaction will favor elimination more than substitution.

64PRACTICE PROBLEM

Which of the given below will favor elimination reaction more than substitution reaction?

65PRACTICE PROBLEM

Three products are formed when the compound shown below undergoes solvolysis in ethanol. Propose a reaction mechanism for each of the products formed.

66PRACTICE PROBLEM

Predict which compound will form a cyclic ether at a higher rate.

67PRACTICE PROBLEM

What happens to the rate of the reaction of 1-bromopentane with ethoxide ion in DMSO if (i) the alkyl halide was changed to 1- iodopentane and if (ii) the alkyl halide was changed to 2-bromopentane? Explain.

68PRACTICE PROBLEM

Draw the major product formed in the following elimination reactions. If the major product formed can exist as stereoisomers, identify the stereoisomer that will be higher in amount and label it as the major product.

i. (R)-2-chloroheptane + high concentration of CH₃CH₂O^–

ii. (R)-3-chloro-3-methyloctane + CH₃CH₂OH

69PRACTICE PROBLEM

Predict the products formed in the reactions shown below.

70PRACTICE PROBLEM

Determine the product for the given reactions. (Note: Show the correct configuration of each product.)

(i) 1-bromo-1-methylcyclopentane + CH₃CH₃O^-

(ii) 1-bromo-1-methylcyclopentane + CH₃CH₂OH

71PRACTICE PROBLEM

Determine the resulting product if the molecule shown below undergoes two consecutive elimination reactions.

72PRACTICE PROBLEM

Draw the major product of the (i) S_N2 and (ii) E2 reactions between (4S,5S)-4-bromo-2,5,7-trimethyloctane and CH₃CH₂O⁻. Note: Show the stereoisomers of the products formed.

73PRACTICE PROBLEM

Identify the products (including stereoisomers) of the reaction between 2-chloro-2-methylhexane and H₂O.

74PRACTICE PROBLEM

Determine the products of the reactions shown below.

(i)

(ii)

75PRACTICE PROBLEM

Can the given reactions form both substitution and elimination products?

(i) 2-chloro-3-methylpentane + NaOH

(ii) 2-chloro-4-methylpentane+ NaOCH₃

(iii) 3-chloro-2,3,4-trimethylpentane + NaOCH₃

76PRACTICE PROBLEM

Can the reaction shown below undergo elimination, substitution, or both? What are its products? Identify the major product.

Reaction 1: 1-bromo-4-methylcyclohexane + NaOCH₃ in CH₃OH

Reaction 2: 1-bromo-4-methylcyclohexane + NaOC(CH₃)₃ in (CH₃)₃COH

77PRACTICE PROBLEM

Explain why one of the stereoisomers below undergoes heat-induced elimination with KOH more rapidly than the other. What are the products of the eliminations?

[Note that the hydrogens are drawn wedged and dashed as a guide.]

78PRACTICE PROBLEM

The silver-assisted solvolysis of (bromomethyl)cyclohexane in ethanol forms methylenecyclohexane. Show the mechanism for the formation of the product.

79PRACTICE PROBLEM

Give the mechanism for the following reaction to rationalize each of the products formed.

80PRACTICE PROBLEM

Draw the product of the following reaction.

meso-3,4-dichlorohexane + t-BuOK →

Note: Syn-coplanar E2 eliminations are rare, usually occurring when free rotation is not possible.

81PRACTICE PROBLEM

Identify if each reaction proceeds via S_N2, E2, S_N1, or E1, and draw the product/s. When more than one product or mechanism is possible, identify which is major and minor.

(i) 3-(iodomethyl)pentane + NaOH in water/ethanol

(ii) 3-(chloromethyl)pentane + AgNO₃ in water/ethanol

82PRACTICE PROBLEM

The solvolysis of 3-(1-bromoethyl)-2,2,4,4-tetramethylpentane can produce several products, including both E1 and S_N1 products, from the unrearranged and rearranged carbocation intermediate. Show all the possible products, including the carbocation intermediate from which they come, and indicate whether they are E1 or S_N1 products.

83PRACTICE PROBLEM

The silver-assisted solvolysis of (bromomethyl)cyclohexane in ethanol forms several products. Propose a mechanism for the formation of the product shown below.

84PRACTICE PROBLEM

The silver-assisted solvolysis of (bromomethyl)cyclohexane in ethanol forms more than one product. Show the mechanism for how the product below was formed.

85PRACTICE PROBLEM

In the silver-assisted solvolysis of (bromomethyl)cyclohexane in ethanol, cycloheptene is one of the products formed. Propose a mechanism for the formation of cycloheptene.

86PRACTICE PROBLEM

A silver-assisted solvolysis of (bromomethyl)cyclohexane in ethanol forms ethoxycycloheptane and other products. Show a reaction mechanism for the formation of ethoxycycloheptane.

87PRACTICE PROBLEM

Given the following:

1-bromo-1-methylcyclopentane + triisopropylamine

Determine if it undergoes either substitution or elimination reaction, and predict the products. Which is the major product?

88PRACTICE PROBLEM

Give the products of the following substitution and elimination reactions.

2-bromo-2-methylbutane heated in methanol.

89PRACTICE PROBLEM

For the following reaction, predict the major and minor elimination products (for now, disregard any potential substitution reactions). Indicate if you anticipate it to be an E1 or E2 reaction.

90PRACTICE PROBLEM

Draw the plausible product(s) and the type of mechanism for the following reaction.

1−bromopentane + sodium methoxide in methanol

If there is more than one plausible product(s), indicate the major product, explain the type of reactions possible, and determine which is most likely.

91PRACTICE PROBLEM

Predict the plausible product(s) and the type of mechanism for the following reaction:

2−bromopentane + sodium ethoxide in ethanol

If there is more than one plausible product, indicate the major product, and explain the type of reactions possible: determine the most likely one. (Ignore stereochemistry.)

92PRACTICE PROBLEM

What product(s) would be formed in the reaction of the following compound with a moderately strong base? Remember: anti-coplanar E2 eliminations are common, while syn-coplanar E2 eliminations rarely occur.