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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5
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1answer
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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 ...
5
votes
1answer
623 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 ...
11
votes
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?
15
votes
1answer
2k views

Resonance in carbocation derived from allenes

During a reaction if addition on one of the $\pi$ bonds of an allene (containing even number of $\pi$ bonds like $\ce {H2C=C=CH2}$) takes place then a carbocation is formed. To decide the position of ...
11
votes
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 ...
9
votes
1answer
8k views

Order of reactivity of carbonyl compounds to Nucleophilic addition reaction

One of the questions in my textbook was to arrange the following in order of their reactivity for nucleophilic addition reaction. $\ce{(p-NO2Ph)_2CO}$ $\ce{(CH3)_2CO}$ $\ce{(p-NO2Ph)COH}$ $\...
3
votes
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{...
3
votes
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 ...