Organic Chemistry
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When a highly electron-rich alkene such as the given 4-methoxystyrene derivative is brominated, trans- and cis-dibromide are produced in approximately equal amounts. Explain this observation.
Determine the product(s) formed in the halogenation reaction below.
Note: Indicate the stereochemistry of the product(s).
Determine the step in the halogenation of the alkene mechanism where the redox reaction happens.
Determine the products formed when the given alkene undergoes a reaction with Cl2.
What is(are) the product(s) formed when the given alkene undergoes a reaction with Br 2.
Determine the product(s) formed when the given compound undergoes a reaction with Cl2.
What is(are) the product(s) formed when the given compound reacts with Br 2.
What are the products formed in the halogenation reaction given below? [Indicate the stereochemistry of the product and any racemic mixtures.]
Identify the missing product(s).
Identify the products for the given reaction and indicate the stereoisomers formed, if any.
In the following reaction, assuming that one equivalent of bromine is employed, determine the major product(s).
Determine which stereoisomer of 4-octene, when it reacts with Cl2, would generate a meso compound.
Identify the major product formed in the reaction given below.
Show how you can make the following compound using 1,2-diethylcyclohexene as the starting material. If a chiral product is shown, you can assume that it is part of a racemic mixture.
Two products are formed in the addition of chlorine (Cl2) to cis-but-2-ene, but only one product is formed in the addition of chlorine (Cl2) to trans-but-2-ene. Give mechanisms to account for this observation. (Making models will be helpful.)
Propose a mechanism and predict the major products of the following reactions. Include stereochemistry in your answers where appropriate.(i) (E)-pent-2-ene + Br2 in CCl4(ii) (Z)-pent-2-ene + Br2 in CCl4
For the following reaction, determine the major product and provide the structure of the reaction intermediate. Include stereochemistry in your answer.
Draw the products that will form from the reaction between the alkene below and with the following reagents: (i) Br2 and (ii) I2.
Show the arrow-pushing mechanism for the following halogenation reaction:
Considering the reaction of enols with bromine, suggest a mechanism for the generation of good yields of α-bromoketone B instead of the dibromide product A.
Predict the products formed in the following reactions:
Draw the product(s) of the reaction below.
Determine the product(s) of the reaction below. Show the stereochemistry and indicate any racemic mixtures.
Unlike the addition of Cl2, HCl addition is not stereospecific. Explain why this is so.
Why doesn’t rearrangement occur in the following bromination reaction despite the proximity of a more substituted carbon?
Reacting 4-methyleneoctane with Cl2, with H2 + Pd/C, or with (1) R2BH/THF (2) HO− + H2O2 generates a racemic mixture. Why?
How can the compound shown below be prepared from an alkene?
Consider how cyclopentene reacts with HCl and how cyclopentene reacts with Cl2. What makes the first step of these two reactions different?
In the reaction of cyclopentene with Cl2, the Cl– adds to the carbon in the cyclic chloronium ion rather than the positively charged chlorine. What is the product formed when the Cl– ion adds to chlorine instead?
Predict the product formed from the reaction of hex-1-ene and ICl.
Starting with an alkene, how can you synthesize the following compound?
What products are formed from the reaction of (i) cis-hex-3-ene with Cl2 in CH2Cl2 and (ii) trans-hex-3-ene with Cl2 in CH2Cl2? Note: Show the stereoisomers of the products.
What are the products of the reaction below? Note: Show the stereoisomers of the products formed.
Give the stereoisomers produced from the reaction between (S)-3,4-dimethylpent-1-ene and Cl2.
Consider the following reaction:
Prove that the reaction of trans-5-methylhex-2-ene with Cl2 produces a cyclic chloronium ion intermediate instead of a carbocation intermediate.
Show how the compound below can be prepared from a cyclic alkene.
Cycloheptene is dissolved in a LiCl/CCl4 solution. Then one equivalent of bromine was added to the solution. A mixture of trans-1,2-dibromocycloheptane and trans-1-bromo-2-chlorocycloheptane was isolated from the reaction. Show the mechanism for the formation of these products.
Halogenation reactions of alkenes proceed via the halonium ion mechanism and form the anti-addition product. However, a mixture of the cis and trans isomers formed in the reaction shown below. Propose a reaction mechanism for the formation of the products and explain why the reaction is not stereospecific.
Show how the following compounds can be synthesized using cyclodecyne as a starting material.
(a) cis-cyclodecene
(b) cyclodecane
(c) trans-1,2-dibromocyclodecane
Addition of Br2 to an unsymmetric cis alkene, like cis-hex-2-ene, results in identical amounts of two enantiomers. Explain why these identical amounts of the two enantiomers are obtained even though the Br− preferably attaches to the less sterically hindered carbon of the intermediate bromonium ion.
Draw a suitable mechanism for the reaction given below.
What is the major product of the reaction between 1-butene and Br2 in the presence of excess Cl− ions? Also, specify the relative amounts of any stereoisomers produced.