Carbocation is a positively charged carbon ion(C+). It is an intermediate generally formed during organic reactions. They exhibit a special quality called 'rearrangement' by virtue of which less stable carbocations can rearrange to form more stable carbocations during the reaction. The actively ...

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How can I- be both a nucleophile and a weak base?

I am just confused as to how $\ce{I-}$ cannot attract $\ce{H+}$, but it can attack a carbocation. It is sharing electrons in both cases, so what is the difference?
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36 views

Cyclopentyl to cyclohexyl carbocation rearrangement

Here is my problem. The mechanism seems pretty straightforward, but I am having trouble converting the cyclopentane to a cyclohexane. During a synthesis problem, does the starting material add the ...
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50 views

How can I predict the product of the reaction of a substituted tetrahydrofuran with HI?

Well, this looks like a pretty straight forward question. But I am getting stuck at the point when preference is being given to the less stable 1° carbocation to form the product. Or am I writing an ...
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55 views

SN1 reactivity order

The question is to compare the SN1 reactivity for the following compounds. According to me it should be like R>S>Q>P. But the correct answer is Q>P>R>S. How can a lone pair donating into a vacant p ...
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72 views

Stability of a carbocation, in part of camphor synthesis

Can someone explain to me why there is a rearrangement reaction of carbocation 1 to carbocation 2? To me the second carbocation appears to be less stable than the first because it is less substituted. ...
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511 views

What is a non-classical carbocation?

What is a non-classical carbocation? How is it different from a classical carbocation? I am confused as I have come across this term many times on Chem.SE but there seems to be nothing for my ...
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Does the carbocation rearrangement in a SN1 reaction specify a change in degree?

I am asked to determine whether the following process is likely to involve a carbocation rearrangement or not: I think it is possible through the rearrangement given above (though the ...
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554 views

Why are tertiary carbocations the most reactive, if they're already stable?

This may seem silly, but doesn't it seem weird for a compound that's stable (in this context, the tertiary carbocation) to be the most reactive? I mean, wouldn't it be the least, given that it's ...
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Ring expansion from a given cyclic carbocation

How will the cyclobutane ring behave in the following case? I initially thought there would be ring expansion to a five membered ring so that there may be less angle strain and a secondary ...
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Benzylic and allylic carbocation stability order

Most books I have read stop at this order : Benzylic > Allylic > Tertiary > secondary > primary However If I want to compare tertiary, secondary and primary benzylic and Allylic carbocations what ...
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Are carbocation intermediates in equilibrium?

So for the reaction of $\ce{H_2O}$ with an alkyl ethene, in the presence of $\ce{D^+}$ ions, forms two possible carbocations: $\ce{ R-CHD-CH2^+}$ and $\ce{R-CH^+-CH2D}$ The major product formed is ...
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Mechanism for acid-catalyzed dehydration of 2,3-dimethylcyclopentanol

How do you get from 2,3-dimethylcyclopentanol to 1,2-dimethylcyclopent-1-ene? I know the -OH group leaves as water (being protonated by acid) forming a carbocation. Then the weak nucleophile (water) ...
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Which carbocation is more stable, the ethyl- or 1-propyl-carbocation?

$\ce{C2H5+ vs \ C3H7+}$ There are two conflicting trends here. Inductive effect of ethyl will be higher than that of methyl so carbocation attached to ethyl (3 carbons in total) should be more ...
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Can Hydride Shift and Methyl shift happen one after another in a carbocation?

Can hydride shift be followed by methyl shift for stabilizing a carbocation? In case both is possible which will occur first?
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Carbocation stability order

I was wondering whether the following order (from here) is correct: In the first inequality, why did 9 hyperconjugations dominated resonance effect of benzene ring? In the last inequality ...
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265 views

How does a carbocation have a positive charge?

When an alkene bonds with an H+ ion, the electron pair from the pi bond goes towards a new dative covalent bond with the hydrogen ion, leaving, on one side of the old double bond, a carbon bonded to ...
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Carbocation rearrangement in alkene addition reaction

This is a question from my textbook: Determine a step-wise $S_N1$ mechanism for the overall reaction: The solution shows the following carbocation rearrangement after Bromine leaves in the ...
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Why cyclopropylmethyl carbocation is more stable Benzyl carbocation?

I know in tri cyclopropylmethyl carbocation the hybridization of carbocation will be pushed to $sp^2$ but how? Can someone explain this to me by drawing resonance structures for tri cyclopropyl methyl ...
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Instability of vinylic and arylic carbocations

I have checked the net a lot and read quite a few books, but I still am not able to understand why vinylic and arylic carbocations are so unstable. Can someone please help For arylic carbocation, the ...
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Stability of cyclobutyl methyl carbocation

I know that cyclopropyl methyl carbocation is exceptionally stable compared to say, benzyl carbocation. But I want to know how stable is cyclobutyl methyl carbocation compared to say, ...
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Why does carbocation stability increase in the order 1°, 2°, 3°?

I'm reading about $\:\mathrm{S_N1}$ and $\:\mathrm{S_N2}$ reaction mechanisms. 1° carbocations are unstable to the point of not having been observed in solution, ever. 2° are more stable, and 3° ...
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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 ...
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Preparation of alkyl halide from alcohols

$\ce{R-OH + HBr -> R-Br + H2O}$ An $\ce{R+}$ carbocation is formed during this reaction. If $\ce{R}$ is any alkyl group instead of methyl or ethyl, can the beta hydrogen to the hydroxy group be ...
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Why are isomers difficult to separate?

I recently learned that attempts to compare the spectra of two isomers of $\ce{C_3H_3^+}$ were frustrated by the difficulty of separating the two species. What makes these isomers difficult to ...
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Precedence of 1,2 carbocation rearrangement

How can one choose which group has more shifting tendency in 1,2 carbocation rearrangement? The obvious order is via the stability of the carbocation of the group. But, phenylic groups have high ...