Questions tagged [c-c-addition]

For questions about addition to C–C π bonds (i.e. C=C or C≡C).

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2
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1answer
32 views

Stereochemical outcomes for hydrohalogenation when there is a carbocation rearrangement

The following reaction is given: I want to be able to tell which of the following stereochemical outcomes are possible. I am aware that there are other possible products than the ones shown here ...
1
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1answer
84 views

What is the meaning of a “halide component” for Friedel–Crafts reaction?

Among the given halides, which one can be used as halide component for Friedel–Crafts reaction? (a) Isopropyl chloride (b) Bromobenzene (c) Chlorobenzene (d) Chloroethene I don't understand what a &...
3
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1answer
144 views

What are the major products when naphthalene reacts with ethyl chloride in the presence of AlCl₃?

From Arihant Test Drive, JEE Advanced 2020; Ramchaya builiding, Daryanganj, New Delhi, India; January 2019, p. 342: Napthalene gives 1-ethylnapthalene on reaction with ethyl choride in the presence ...
7
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1answer
244 views

Electrophillic susbtitution of bromine on styrene and cinnamic acid in the presence of FeBr3, a Lewis acid

Bromine gas, in the presence of $\ce{CCl4}$, undergoes on addition reaction at the double bond in both styrene and cinnamic acid, illustrated below. Styrene: Cinnamic acid: Bromination of benzene in ...
3
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1answer
73 views

The dependency on electron density in the reactivity order of electrophilic and nucleophilic additions

It is well-known that for electrophilic addition across an alkene, the reactivity increases when intermediate carbocation is more stable (eg. addition of $\ce{HBr}$ or acid-catalyzed addition of $\ce{...
6
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3answers
251 views

Does rearrangement take place in the reaction between ethenylcyclohexane and iodine chloride?

I am stuck at the point if a non classical carbocation should be formed on the 2nd Carbon of the side chain. One of my friend gave me the following suggestion: I guess $\ce{ICl}$ will break in the ...
3
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0answers
4k views

What is the major product of the reaction of 2-methylbuta-1,3-diene with HBr? [duplicate]

What is the product of the reaction of 2-methylbuta-1,3-diene (isoprene) with HBr? What I understand is that carbon (2) will get a positive charge after protonation. But after this, which should be ...
11
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1answer
1k views

Why does boron add to the less substituted carbon in the hydroboration of an alkene?

In the hydroboration of a typical alkene, the boron fragment ends up attached to the less substituted carbon: What are the electronic or steric factors that lead to this regioselectivity?
11
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3answers
2k views

Getting 3,4-dimethylhex-3-ene from but-2-ene

How can one get 3,4-dimethylhex-3-ene from but-2-ene ? $\hskip2in$ Using $\ce{Br_2}$ then two equivalents of $\ce{CH_3CH_2MgBr}$, I can get the corresponding alkane (3,4-dimethylhexane) but I don't ...
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0answers
29 views

Addition of 1 equivalent bromine to 1,3 pentadiene at temperature below 0 degree Celsius gives which compound?

As far as I know reactivity of alkenes towards addition with halogens is directly proportional to their nucleophilicity, so bromine in this particular case should attack the double bond at Carbon-3 ...
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66 views

Stereochemistry of the product of crotonic acid with bromine

Is there a a simple rule for determining the stereochemistry for the product of a reaction between an unsymmetrical alkene like (2E)-but-2-enoic acid and bromine (anti reaction)? If it's an anti ...
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1answer
32 views

Addition reaction of alkenes [closed]

During an addition reaction of an alkene, how does a double bond break to form two bonds with the two atoms of the reactant plus a bond between the carbon atoms? Not sure if this is a silly question ...
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2answers
457 views

Markovnikov Rule of Alkenes

$$\ce{CH3CH(CH3)CHCHCH2CH3 + HBr ->}$$ According to Markovnikov Rule, "the rich get richer". But, as we can see the 2 carbons have the same amount of $\ce{H}$. So, what's probably the answer?
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1answer
114 views

Regioselectivity of electrophilic addition of Halogen and Water (Halohydrin) on Alkenes?

I am currently studying for an organic chemistry exam and I just couldn't come up with a solution to the following question: Consider the reaction of 1-Propene + Br2 with water as solvent. Why will ...
4
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2answers
151 views

Stereoselectivity of ring closure in intramolecular iodolactonisation

What is the product of the reaction above? I am mainly confused between the following two options: How do we decide the resulting stereochemistry of the $\ce{CH_2I}$ group? The answer given is the ...
0
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1answer
164 views

What are the products of alkene oxymercuration with diols?

I was wondering what would be the product of the reaction of alkene with a diol (such as glycol) in alkoxymerucuration/demercuration, i.e. $\ce{(CF3CO2)2Hg/NaBH4}$? I tried to look online but I couldn'...
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0answers
50 views

In what case would water attack the least substituted carbon in an oxymercuration–demercuration reaction? [closed]

I understand that oxymercuration–demercuration is textbook Markovnikov. However, in a case like this, where the $\ce{OH}$ is formed on the least substituted carbon (secondary) rather than the most ...
9
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1answer
1k views

Reaction of vinylacetylene (but-1-en-3-yne) with HCl

Vinylacetylene contains both a double bond and a triple bond. We know that alkenes are more reactive to electrophillic addition reactions, so I thought that the $\ce{H+}$ from $\ce{HCl}$ would get ...
2
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0answers
49 views

How is elimination reaction (E1) possible without base and in presence of acid?

When learning about E1 we were taught that three things are important factors to judge if the reaction is E1 or E2 Substrate ( 3,2,1 favours E2 but only 3 favours E1 ) Base ( Stronger Base favours E2 ...
2
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1answer
124 views

Why alkyl shift happens during hydroboration oxidation?

In this oxidation step, where alkyl shift happens for 3 times to kick out the OH- to obtain the boron-ester. But why does this happen? Won't the boron atom become less stable as the empty p orbital is ...
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1answer
71 views

Ozonolysis of alkene

(from Wikipedia) I am having trouble in the last step where the alkene ozonide is reduced to ketones / aldehydes specifically in the presence of water. My teacher is telling me that water will be ...
4
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1answer
145 views

Method for regioselective hydroalkylation of terminal alkyne

I'm trying to figure out a method to add a linear alkyl chain R and a hydrogen atom H across the triple bond of a terminal alkyne. The alkyl chain should end up on the internal carbon (C-2): My ...
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0answers
47 views

Is it possible to produce an epoxide from 2-bromoacetyl bromide using methyl magnesium bromide

This is also one of the questions from practice papers for the JEE , asks for 2 step reaction for epoxidation of ketene For product A , π complex is generated on c-c bond since carbon labelled 1 is ...
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65 views

Can Diels-Alder reaction occur using reagents of Robinson annulation?

Robinson annulation seemed somewhat like the Diels-Alder reaction to me, if all ketonic groups were to be represented as enol then cyclohexanone would be like diene and the Michael acceptor as a ...
5
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1answer
2k views

Markovnikov's addition to halogenated alkene?

The justification or rather intuition behind Markovnikov's rule is the stability of intermediate carbocation. The more substituted the carbocation the more stable the product. But based on this ideas ...
2
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2answers
219 views

Anti-Markovnikov addition of HCl

The following reaction has been troubling me for a while now. Since peroxides won't give the anti-Markovnikov product when used with HCl, I cannot think of any reagents that would result in the ...
2
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1answer
89 views

Addition to equally substituted carbons

I was wondering whether there is a trick in the following problem: Since both carbons are equally substituted, shouldn't the products be the same with or without the use of peroxides?
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0answers
892 views

Reaction of alkenes with AlCl3/HCl

I stumbled upon an interesting organic chemistry problem: Previously I thought $\ce{AlCl3}$ would only be used with benzene in acylation and alkylation, but apparently it can also be used in ...
3
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1answer
125 views

How can a β,γ-unsaturated ketone be converted to 1-pyrroline?

I am working towards a natural product. Presented are three intermediate compounds. After oxidation of the hydroxyl to a carbonyl, I want to introduce an imino-nitrogen atom into the structure. This ...
4
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1answer
684 views

Can someone explain my professor's answers for these alkene additions? [closed]

(a) Why would cyclohexane expand into cycloheptane? Cyclohexane is stable. (b) Why would cyclopentane not ring expand into cyclohexane? In the process a tertiary carbocation would be formed just like ...
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0answers
135 views

Varying sizes in LUMO of acrolein

I want to ask a question about the varying sizes in the LUMO of acrolein during a 1,2- or 1,4-addition. Today in our introductory lesson to Organic Synthesis with 1,2- and 1,4-addition we were ...
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0answers
242 views

If alkyl-substituted alkenes are more stable, how does one explain their increased addition reactivity?

My understanding is that in alkyl-substituted alkenes there is hyperconjugation between $𝜎(\ce{C−X})$ and $𝜋^∗(\ce{C=C})$. I also have read that more alkyl-substituted alkenes are many folds more ...
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2answers
6k views

Reactivity order in hydrogenation reaction of but-2-yne and butene isomers

Question 1: The reactivity order towards hydrogenation of the following compounds is: but-2-yne ($\ce{CH3-C\bond{3}C-CH3}$) cis-but-2-ene ($\ce{CH3-CH=CH-CH3}$) trans-but-2-ene ($\ce{...
5
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1answer
232 views

Intramolecular lactonisation in an unsaturated carboxylic acid

I am having some trouble figuring out how this reaction proceeds: Attempt 1: The most obvious thing to do is deprotonate the acid group. I tried using the carboxylate group to attack the alkene, ...
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0answers
35 views

Addition v/s elimination with double bond and OH together

If a compound has both an hydroxyl group and a double bond and we add $\ce{HBr}$ to it, (a) substitution reaction to the hydroxyl group can take place, or (b) an addition reaction of a double bond can ...
7
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1answer
1k views

Why does the chlorination of indene occur with syn selectivity in heptane?

In the chlorination of indene to form 1,2-dichloro-2,3-dihydro-1​H-indene in heptane as solvent, the syn dichloride is formed as the major product, as reported in J. Org. Chem. 1980, 45 (25), 5150–...
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0answers
395 views

Shouldn't the 5-membered ring expand to a six membered one in this nucleophilic addition reaction?

I am dealing with a problem involving addition of $\ce{HCl}$ to a ring: According to what I think, the ring should expand to a six-membered following carbocation formation at the tertiary site, as a ...
7
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2answers
2k views

Hydroboration/oxidation vs acid-catalyzed hydration of 1-phenylpropene

I am trying to predict the products of both the hydroboration/oxidation and acid-catalyzed hydration of 1-phenylpropene: Both C1 and C2 of the double bond are secondary carbons. However, I have the ...
8
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1answer
5k views

What is the difference between "bromine" and "bromine water" in their reaction with an alkene?

In question 16 of the A-Level Chemistry 2013 exam, there is this reaction scheme: $$\ce{CH3CH=CH2 ->[?] CH3-CHBr-CH2Br}$$ The question asks for both the name of the reagent and the product. I ...
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1answer
2k views

What is Markovnikov's rule?

What is Markovnikov's rule? How can we use it to predict the products of additions to alkenes? And is it always obeyed, or are there exceptions to this rule?
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1answer
1k views

Regioselectivity in Kharasch addition of bromotrichloromethane

When hex-1-ene is treated with bromotrichloromethane in the presence of a peroxide initiator (e.g. dibenzoyl peroxide), what is the regioselectivity of the addition? I know that the radical addition ...
2
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1answer
3k views

What is the stereochemistry resulting from hydroboration of 1-methylcyclopentene?

What is the major product of the following reaction sequence? I'm supposed to work out the structures of both 2 and 3, but I already know 2 to be 1-methylcyclopentene (as the most substituted ...
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0answers
2k views

Electrophilic addition of IBr to alkene

I would assume options A and B are possible products due to the $\ce{I+}$ electrophile attacking the alkene, and hence are ruled out. However, I am torn between options C and D. Both products are ...
2
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1answer
383 views

On the addition of HCl to a conjugated diene [closed]

Is this allylic chloride formed by an ionic or radical mechanism? Is it the more stable isomer?
2
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1answer
1k views

Why do more substituted alkenes undergo epoxidation, but the less substituted alkenes undergo hydrogenation?

We know that, in case of a choice, catalytic hydrogenation will hydrogenate the less substituted alkene, because the less substituted alkene is less stable. But, we also know that, in case of a ...
5
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1answer
626 views

Regioselectivity of bromination of alkenes

Recently, in my chemistry lesson, we were discussing the mechanism of the bromination of alkenes. The teacher brought up the involvement of the cyclic bromonium intermediate. She also mentioned that ...
3
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0answers
162 views

Mechanism of photochemical hydroamination with LDA

I've recently come across a couple examples of intramolecular alkene hydroamination accomplished by treatment with LDA followed by visible light irradiation (tungsten light bulb):[1,2] I'd assume ...
0
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1answer
987 views

Regioselectivity in addition of hydrogen iodide to vinyl chloride

I encountered a question which was stated as: The reaction of vinyl chloride with hydrogen iodide to give 1-chloro-1-iodoethane is an example of anti-Markovnikov addition. Is this true or false? ...
3
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2answers
665 views

Product of the addition of 1 eq. bromine to 1-methylcyclohexa-1,4-diene

When we add one equivalent of $\ce{Br2}$ then which double bond will get brominated? The double bond in the molecule with methyl group will be more stable as it will have more hyper conjugating ...
2
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1answer
228 views

Products for the hydrogenation of the cycloalkene in (3R,4R,5S)-4,5-diamino-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylic acid

Write the products (more than one) for the hydrogenation of the cycloalkene ring in (3⁠R,4⁠R,5⁠S)-4,5-diamino-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylic acid. Reagents are molecular hydrogen with ...