Organic Chemistry
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Draw an electron-pushing mechanism for the S N2 reaction shown below.
Provide an electron-pushing mechanism for the SN2 reaction shown below.
Draw the structure of the transition state for the S N2 reaction shown below.
Which of the following S N2 reactions would proceed faster? Explain why.
Which of the following haloalkanes would undergo an S N2 reaction more readily?
Which of the following haloalkanes would undergo an SN2 reaction more quickly?
Does a more sterically hindered alkyl halide correspond to a slower or faster SN2 reaction rate?
Determine which alkyl halide is more reactive with a certain nucleophile in an SN2 reaction.
In an SN2 reaction, sort the given alkyl chlorides from most to least reactive: 1-chloro-3-methylhexane, 1-chloro-2-methylhexane, 2-chloro-2-methylhexane, and 1-chloroheptane.
In an SN2 reaction, determine which alkyl halide is more reactive in each pair of substrates.
For the reaction given below, provide a suitable mechanism that illustrates why the retention of the reactant's configuration at the chiral center is observed in the product.
For the SN2 reactions given below, draw the products formed between:a. (5S)-5-chloro-2,3-dimethylheptane and hydroxide ion
b. 4-bromo-2,6-dimethylheptane and hydroxide ion
What are the structures of the products formed from the given SN2 reactions?
(a) 1-ethyl-3-iodocyclobutane and methoxide ion
(b) 1-chloro-4-isopropylcyclohexane and propoxide ion
The synthesis of 2,3-dihydrobenzo[b][1,4]dioxine-2,3-dicarboxylic acid is illustrated here:
(a) Illustrate the mechanism by which A is converted to B.
(b) Which is formed faster between A and B?
Which member in each of the given pairs of compounds will undergo SN2 at a faster rate?
Give the substitution products formed in each of the SN2 reactions given below.a. CH3ONa + CH3Br →b.
Give the substitution products formed in each of the SN2 reactions given below.
Determine the major substitution products formed in each of the reactions given below.
Which member in each of the given pairs of compounds is better at SN2 reactions?(a) cyclopentyl iodide or 1-iodo-1-methylcyclopentane(b) tert-butyl bromide or 2-methyl-1-bromopropane
Determine the major substitution products formed in the given reaction.a. CH3C≡C:− Na+ + CH3CH2Br →
Give the major substitution products formed in the given reaction.a. CH3Cl + KCN →
Provide the major substitution products formed in the given reaction.a. 1-Bromobutane + KI →
True or False: The SN2 reaction is the concerted, frontside displacement of a leaving group by a nucleophile. Explain your answer.
In which solvent does the SN2 reaction below proceed at higher rate? THF or NH3?
Crown ethers can solvate cations as shown below where the 18-crown-6 forms a stable complex with potassium. How is the rate of an SN2 reaction affected by the addition of a crown ether?
Why does the following reaction still occur via an SN2 reaction even though run under standard solvolysis conditions?
Which of the two haloalkanes would undergo SN2 reaction more readily?
Draw the product(s) that would result when the given molecule is subjected to the following reaction conditions. Write “NR” if there is no reaction.
Provide the mechanism for the SN2 reaction below.
Choose the nucleophile that is expected to react at a faster rate in an SN2 reaction if it uses water as the solvent.
Choose the haloalkane that is expected to react at a faster rate in an SN2 reaction.
Which of the solvents propanol or methyl tert-butyl ether would tilt the equilibrium further to the right? Assume an SN2 mechanism.
How is the relative rate of SN2 expected to change when the reaction below is carried out in a solvent with greater polarity?
What are the products (including stereochemistry) that are produced when the given reagent reacts with the trans configuration of (2-chlorocyclohexyl)(phenyl)sulfane?
How is the relative rate of SN2 expected to change when the reaction shown is carried out in a solvent with greater polarity?
A methyl halide or a primary alkyl halide works best for SN2 reactions. Explain.
Which solvent between ethanol and acetonitrile makes the propionate ion a better nucleophile in an SN2 reaction with a primary alkyl halide?
Provide the Fischer projection of the product of the SN2 reaction shown below.
Provide the perspective structure of the product of the SN2 reaction shown below.
Consider the following pair of compounds:
(i) 1-bromo-2-methylpropane or 3-bromopentane
(ii) 2-chloropentane or 1-chloro-3-methylbutane
(iii) 1-fluoro-2-methylbutane or 2-fluoro-3-methylbutane
Identify the better SN2 substrate.
Which compound in the given pairs would undergo an SN2 reaction more rapidly?
Trimethyloxonium tetrafluoroborate, (CH3)3O+BF4−, is a white solid and a strong alkylating reagent. Show how it can transfer a methyl group to a nucleophile (Nuc:−) via SN2. Label the leaving group. Briefly explain what makes this alkylating reagent easier to handle than most methyl halides.
Consider the SN2 reaction of 1-chloro-3-methylpentane with a large excess of ammonia (NH3). Draw the reactants, the transition states, and the products.
Provide the product structure formed by the SN2 reactions below in perspective or Fisher projection form.
a) cis-1-chloro-3-ethylcylopentane + NaOH
b) (S)-2-chlorobutane + KCN
Draw the product structure formed by the SN2 reactions below in perspective or Fischer projection form.
What are the major products of the reactions shown below?
(i) tosylate of cyclopentylmethanol + excess NH3
(ii) n-propyl tosylate + sodium acetylide
If the following compounds undergo SN2 with sodium methoxide (Na+ −OCH3) in methanol, what is their order of decreasing reactivity?
(i) 3-bromo-3-methylpentane
(ii) ethyl iodide
(iii) 2-chloro-2-methylbutane
(iv) 1-chloro-3,3-dimethylbutane
(v) isopropyl iodide
(vi) 2-bromobutane
When (±)−2,3-dibromopentane reacts with sodium hydroxide, they form the following products.
Explain why there is no formation of cis-2-bromopent-2-ene.
Choose the compound that reacts faster via the SN2 mechanism.
True or False: A much higher yield of a primary amine is obtained from the reaction of an alkyl halide with potassium phthalimide followed by hydrolysis because potassium phthalimide upon alkylation loses its nucleophilicity and thus does not react further with the alkyl halide to form tertiary amides.
A student conducted experiments wherein he used toluene solvent to measure the reaction rates of (i) ethyl bromide with pyridine and (ii) ethyl bromide with diisopropylamine. The concentration of reagents remained identical in both experiments. Which SN2 reaction exhibited the higher rate constant?
Briefly explain why the alkyl halide shown reacts much more rapidly with guanine than a primary alkyl halide like 1-bromobutane.
The reaction of (R)-1-fluoro-1-iodopropane with sodium ethoxide is given below.(R)-1-fluoro-1-iodopropane + sodium ethoxide → (R)-1-ethoxy-1-fluoropropane + NaIa. Draw perspective structures of the reactants, transition state, and the products.b. Is there a retention or inversion of configuration in the product? Is this consistent with the SN2 reactions?c. Why is iodide substituted and not fluorine?
Choose the SN2 reaction that is expected to proceed at a faster rate. Provide an explanation using an energy diagram.
Determine the stereoisomer formed in the reaction below.
Propose a mechanism for the reaction below:
Despite being neutral, amines are deemed to be good nucleophiles. For the S N2 reaction of an amine and an alkyl halide, determine the rate of the reaction when the polarity of the solvent is increased.
Determine the change of the reaction rate if the given SN2 reaction is carried through a more polar solvent.
CH3C(CH3)2CH2CH2CH2Br + OH- → CH3C(CH3)2CH2CH2CH2OH + Br-
A stereospecific reaction of 2-(tosyloxy)cyclopentyl propionate and propionate produces a product dependent on the substrate's stereoisomer. The substrate has four stereoisomers — two are cis and the other are trans—due to two asymmetric centers. Explain the observations made below.
When the reactants are both cis, it will form an optically active trans product, but each substrate would form different trans product.
A stereospecific reaction of 2-(tosyloxy)cyclopentyl propionate and propionate produces a product that is dependent on the stereoisomer of the substrate. Because of the two asymmetric centers, the substrate has four stereoisomers: two cis and two trans. Explain the observations made below:
A trans substrate is more reactive than a cis substrate.
For the following substitution reactions, determine which would react faster.
CH3CH(CH3)CH2CH2I + HO− or CH3CH2CH2CH(CH3)I + HO−
For the following substitution reactions taking place in ethanol, determine which reaction would be faster.
CH3CH2CH2Br + CH3CH2O− or CH3CH2CH2Br + CH3CH2S−
Determine the nucleophile used in a reaction with 1-bromo-3,3-dimethylbutane to form the following compound:
Propose a reaction to synthesize isobutoxycyclopentane from an alkyl halide.
Propose a reaction to synthesize 1-propoxypropane from an alkyl halide.
A stereospecific reaction of 2-(tosyloxy)cyclopentyl propionate and propionate produces a product dependent on the substrate's stereoisomer. The substrate has four stereoisomers — two are cis and the other are trans— due to two asymmetric centers. When both trans reactants undergo the reaction, they produce the same product. Why?
The ethyl chloride reaction rate with 1-azabicyclo[2.2.1]hepta-2,5-diene was first measured using nitrobenzene. Using the same solvent, the rate of reaction of triisobutylamine was also measured. Both experiments were done using the same concentration of reagents.
Determine the reaction with the more significant rate constant when the experiment uses 3-chloropentane instead of ethyl chloride.
Determine the alkyl halide that would have the larger k1-azabicyclo[2.2.1]hepta-2,5-diene/ktriisobutylamine ratio.
Propose a reaction for the synthesis of 1-(isopentyloxy)-3-methylbutane from an alkyl halide.
The rate of the SN2 reaction given below changes with the polarity of the solvent. Explain this sensitivity towards the polarity of the solvent and draw an energy diagram for this reaction to show whether it will be faster in a more polar or less polar solvent.
The reaction of sodium ethoxide with 1-chloropropane forms 1-ethoxypropane. Write another SN2 reaction using different reagents that will yield the same product.
Use a bimolecular substitution reaction (SN2) to convert allyl bromide into these compounds:
Use a bimolecular substitution reaction (SN2) to convert ethyl iodide into these compounds:
Use a bimolecular substitution reaction (SN2) to convert an alkyl halide into these compounds:
Give two synthetic approaches to this compound employing SN2 reaction. Discuss which approach is better.