Organic Chemistry
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Without any knowledge of the mechanism for following substitution reaction:
Predict the ratio of the products formed for the reaction (in whole numbers) based on random statistical distribution when iodine (I) replaces hydrogen (H) in isopentane (C5H12).
Determine the major product of the monohalogenation reaction of the alkane given below. State whether you believe the reaction is selective and explain why.
Reaction (a) shown below produces an unequal mixture of products while reaction (b) produces an equal (racemic) mixture of products. Explain why.
Draw the major product formed in the benzylic bromination reaction shown below.
In the following free radical halogenation reaction, one of the products is formed in excess. Identify which stereoisomer is the major product.
In the following free radical halogenation reaction, one of the products is formed in excess. Explain why this reaction yields an unequal mixture of products.
Predict the missing products in the free radical halogenation reaction shown below. Ignore stereoisomers.
Is it possible to make the following primary bromoalkane in good yield using the alkane halogenation reaction? Justify your answer.
Draw the major product obtained in the free radical halogenation reaction given below.
What would be the major product formed in the free radical bromination reaction given below?
Draw a suitable mechanism for the free radical bromination reaction given below.
Consider the following reaction and identify the weakest bond (a, b, or c) in the given molecule.
Determine why the marked bond in the following reaction is the weakest bond.
Draw a plausible mechanism for the following chlorination reaction. Hint: The movement of a single electron is represented using a fishhook arrow.
Predict the number of alkyl bromides expected from the monobromination of the alkane given below. Do not include stereoisomers.
Determine the number of alkyl bromides expected from the monobromination of the alkane given below. Do not include stereoisomers.
How many monobrominated products are expected from the alkane given below? Do not include stereoisomers.
Determine the number of alkyl chlorides expected from the monochlorination of the alkane given below. Do not include stereoisomers.
Determine the number of alkyl bromide expected from the monobromination of the alkane given below. Do not include stereoisomers.
Predict the number of alkyl halides expected from the monobromination of the alkane given below. Include stereoisomers.
Predict the number of alkyl bromides expected from the monobromination of the alkane given below. Include stereoisomers.
Determine the number of alkyl halides expected from the monobromination of the alkane given below. Include stereoisomers.
Determine the number of alkyl halides expected from the monochlorination of the alkane given below. Include stereoisomers.
Determine the number of alkyl bromides obtained from the monobromination of the alkane given below. Include stereoisomers.
Draw the product of the following reaction.
Draw the monochlorinated product obtained in the given reaction. Do not show stereochemistry.
Draw the product obtained from the given reaction. No need to show stereochemistry.
Draw the possible product(s) of the given monochlorination reaction. Do not show stereochemistry.
What is the major monobrominated product formed when the following compound is heated with Br2? Disregard stereoisomers.
Draw the major monochlorinated product obtained in the following reaction. Disregard stereoisomers.
What is the major product of the following reaction? No need to include stereoisomers.
What is the major product of the following reaction? Do not include stereoisomers.
Which isomer with formula C7H16 forms only three monobrominated products (one primary, one secondary, and one tertiary)? Two of these products are achiral and one is chiral.
Which isomer with formula C7H16 forms only three monobrominated products? All of these products are achiral.
Why does iodine not react with methane under ordinary conditions, even though I2 is cleaved easily to form radicals?
Draw the major monobrominated product(s) obtained in the reaction given below. Include stereochemistry if applicable.
Write the mechanism of the monochlorination of cyclopentane, including initiation, propagation, and termination.
When propane is chlorinated, a mixture of products is obtained. Draw the structures of all the monochlorinated products present in this mixture.
Determine the ratio of monochlorinated products obtained by chlorination of butane. Assuming that all the hydrogen atoms can be substituted at the same rate.
Cyclopentene undergoes light-promoted bromination as shown below. Propose a mechanism for this reaction.
Draw all the possible monochlorinated products for each of the following alkanes.a. 2-methylbutaneb. 2,2-dimethylpropane
Which monobrominated product would be produced in good yield by the free-radical bromination of the following alkanes?a. 2-methylbutaneb. 2,2-dimethylpropane
Cyclopentane undergoes light-promoted chlorination as shown below. Propose a mechanism for this reaction and label the initiation and propagation steps.
When one mole of bromine is mixed with one mole of methane in the presence of light, then a mixture of di- tri- and tetrabromomethane is obtained along with some unreacted methane.(a) Explain why a mixture of products is formed even if the reactants were in the same stoichiometric ratio.(b) Show how these compounds are formed from bromomethane.
Hydrogen peroxide is often used as an initiator in free-radical chlorination reactions because the oxygen-oxygen bond undergoes homolytic cleavage easily compared to the chlorine-chlorine bond.Propose a mechanism for the H2O2-initiated chlorination of cyclohexane.
Show how ethylbenzene can be converted to the product shown below using a single-step reaction.
3-Methylbut-1-ene gives two substitution products when treated with a low concentration of bromine under irradiation by a sunlamp.Propose a mechanism to show the formation of these two products.
Propose a free-radical halogenation reaction to synthesize each of the compounds given below. Also, provide a reason why we get a single major product in each of these reactions.a. 1-Chlorocyclopentaneb. 2-Bromo-2-methylpentane
Explain how would an industry control the ratio of methane and bromine.a. To synthesize a good amount of CBr4?b. To synthesize a good amount of CH3Br?
When pentane is reacted with chlorine in the presence of light, a poor yield of 1-chloropentane is obtained. However, cyclopentane can be converted to chlorocyclopentane with good yield by the same reaction.a. Explain this difference.b. What should be the ratio of reactants to get a good yield of chlorocyclopentane.
Cyclopropanes tend to open up in the presence of nearby radicals because of angle strain. Draw a mechanism for the reaction below.
Commercial supplies of the solvent tetrahydrofuran (THF) are often stabilized with a small amount of BHT to prevent autoxidation upon exposure to air. Draw the mechanism that shows how BHT intercepts autoxidation. Assume that the initiation step is caused by a generic R radical.
Assuming that the desired product for each reaction is the tertiary alkyl halide:
i. What is the atom economy of each reaction?
ii. Based on this metric, which reaction would be considered greener? Explain.
Assuming that the desired product for each reaction is the tertiary alkyl halide. i. What is the E-factor for each reaction? ii. Which reaction would you consider greener? Explain.
Assuming that the desired product for each reaction is the tertiary alkyl halide: i. What is the effective mass yield (EMY) for each reaction? ii. Which reaction would you consider greener? Explain.
Assuming that the desired product for each reaction is a tertiary alkyl halide: i. What is the process mass intensity (PMI) for each reaction? ii. Which reaction would you consider greener? Explain.
Tributyltin hydride, (C4H9)3SnH, is often used as a “chain propagating radical”. Is the Sn ― H or C― H expected to be stronger? Which one will form a more stable radical? Justify your answer.
The following reaction intended to make molecule (i) but formed molecule (ii) instead. Draw the mechanism for the formation of molecule (ii).
The following reaction intended to make molecule (i) but formed molecule (ii) instead. Which marked C-H bond is expected to have a lower bond-dissociation energy?
For the reaction below, draw the major monohalogenation product(s). Identify if the reaction is selective and justify it.
Give the monohalogenation product(s) of the reaction shown below. If the reaction is selective, draw only the major product(s). Otherwise, draw all possible products.
Provide the monohalogenation product(s) of the reaction shown below. If the reaction is selective, draw only the major product(s). Otherwise, draw all possible products.
Choose the best reaction to represent the properties of radical halogenation.
Draw the arrow-pushing mechanism for the bromination of cyclopentane. Only draw three possible termination steps.
A radical reaction involves the following radical species in its propagation steps. Draw the 6 possible products from the termination steps.
Draw the arrow-pushing mechanism, including the initiation and the two propagation steps for the following reaction.
True or False: In the second propagation step in the bromination of toluene, the bromine molecule is more likely to add to the aromatic ring than to the benzyl position due to the stability of the benzyl radical.
What product/s would form in the allylic bromination reaction shown? (Note: Ignore stereochemistry.)
Determine the carbon in the given radical where the new C-Br bond is most likely to form in the second propagation step of the free radical bromination using NBS. [Ignore stereochemistry.]
Supply the products in the free radical halogenation reaction given below. Do not include stereoisomers.
ACBN is a molecule that can be used as an initiator in a radical reaction. Draw the mechanism of the formation of the given radical molecule and determine the driving force for this reaction.
As shown below, a haloalkane can be reduced into an alkane using Bu3SnH and AIBN.
Draw the mechanism of the reaction.
In carrying out radical cyclization, we can use Bu3SnH and a small amount of AIBN. Draw the mechanism for the following cyclization reaction.
An alkane has a molecular formula of C8H18 and can only form a single product when it reacts with Cl2 under light. Draw its structure.
In the presence of an acid catalyst, formaldehyde forms a trimer known as trioxane. Propose a mechanism for the formation of trioxane.
Draw the mechanism for the reaction below.
Consider the bromination of isobutane. Will the rate of the reaction increase, decrease, or remain unchanged when HBr is added to the reaction mixture? Explain your answer.
Determine the number of products formed by the monochlorination reaction of the following alkane when stereoisomers are included.
Determine the number of products formed by the monochlorination reaction of the given alkane, including stereoisomers.
Determine how many products would be obtained from the cycloalkane's monochlorination reaction if all its stereoisomers are included.
Determine the major product for the reaction of the given cycloalkane with Cl2 in UV light. Ignore stereochemistry.
How many products are formed from the radical chlorination of methylcyclopentane? (Ignore stereoisomers.)
True or false. The following steps are involved in the formation of tetrabromomethane (CBr4) from the reaction of methane with Br2 in the presence of light:
Consider the mechanisms for the monobromination of methane involving the propagation steps shown below:
How do you know the monobromination reaction does not occur via the alternative mechanism?
The equation below defines the deuterium kinetic isotope effect for the halogenation of an alkane (X・ = Cl・ or Br・). Is the deuterium kinetic isotope effect greater in chlorination or bromination?
Synthesize cycloheptene from cycloheptane (not by dehydrogenation).
Why is the following free-radical chlorination of ethane incorrect based on experimental evidence?
Consider the following free-radical chlorination:
What is its mechanism?
The reaction below proceeds in the presence of light and a small amount of bromine.
Why does cyclopentene react with bromine much faster than cyclopentane, which requires heat to react?
Consider the second propagation step in the chlorination of ethane:
What is the structure of its transition state? Is the transition state reactant-like or product-like? Which partial bond in the transition state is stronger?
Consider the free radical iodination of ethane,
Provide two reasons why iodine does not react favorably with ethane.
Consider the following abstraction of a secondary hydrogen and a primary hydrogen from butane using an iodine radical:
What is the enthalpy of reaction for each abstraction?
In general, alkyl radicals are less stable than alkoxy radicals. (i) What is the equation for the alkyl free radical abstraction of the alcohol hydrogen atom from 2-methylbutan-2-ol? (ii) What is the reason for being able to use 2-methylbutan-2-ol as an antiknock additive in gasoline?
Using the provided starting material, devise the synthesis pathway for the given compound.
You are conducting a chlorination reaction where 1 mole of ethane is mixed with 1 mole of chlorine. The products contain significant amounts of monochlorinated and polychlorinated products, along with unreacted ethane. How would you modify the experiment to obtain a good ethane conversion to C2H5Cl? Of ethane to C2Cl6?
Provide the initiation step reaction for the monobromination of methane.
Draw all the possible monobrominated derivatives of each of the alkanes listed below.
a. 2-methylpropane
b. 2-methylbutane
Determine whether the free-radical monobromination of each alkane listed below produces a single product.
a. cyclohexane
b. propane
The free-radical halogenation reaction usually generates a mixture of substitution products. Rationalize.