Questions tagged [carbocation]
Carbocations are species bearing a positive charge on carbon. They are intermediates generally formed during organic reactions, which can be stabilised by various electronic effects. Less stable carbocations are capable of undergoing rearrangements to form more stable carbocations in the course of a reaction.
226
questions
5
votes
1
answer
427
views
What is the product of reaction between 3,3-dimethyl butanal and SeO2 followed by conc. OH- ions?
So basically first step will be replacement of $\ce{-CH2 -}$ by a ($\ce{=O}$ bond) making a aldehyde and ketone side by side. Now what should I do after this? I tried attacking the aldehyde first as ...
- 517
0
votes
0
answers
97
views
Which of the following compound will undergo rearangement?
Question
Attempt
I believe the answer should be B,C and D. In C and D the oxyge(or Nitrogen in D) can rearange by donating lone pair to carbocation.
But the books answer says B. Where am I wrong. ...
- 623
0
votes
3
answers
401
views
Odd looking carbocation stability order [duplicate]
I am studying introductory organic chemistry, suddenly this one started looking odd,
The carbocation stability for three compounds as given by my book is shown below,
Let me call those as ...
user91694
8
votes
2
answers
2k
views
False positive in lucas test for primary alcohol due to formation of tertiary carbocation by rearrangement?
From Wikipedia:
The Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. It is based on the differences in reactivity of the three classes of alcohols ...
- 193
1
vote
1
answer
555
views
Can a reaction have carbocation resonance followed by a hydride shift?
Consider 5-methylcyclopentadiene:
If HX attacks at carbon 1, we have an option of 1,2 or 1,4 (carbocation resonance) addition. In the case of 1,4 addition, since the carbocation (secondary) will be ...
- 186
3
votes
1
answer
3k
views
Resonance structures of 4‐aminobut‐3‐en‐2‐ylium
Problem
How many resonance structures can be drawn for the following molecule?
(a) 1
(b) 4
(c) 3
(d) 2
Answer
Question
I think that the molecule can be drawn in three ways, which contradicts the ...
- 179
1
vote
1
answer
393
views
Intramolecular Reaction with carbocation rearrangement
I came across a question recently which is as follows,
I came up with a mechanism but I am stuck at a step as I am unable to reason out the driving force.
Step(3) has a hydride shift and its next ...
- 1,244
1
vote
1
answer
378
views
What is the stability order of the carbocation and carboanion?
So I came up with examples as below:
1
2
Now I am confused about the +I and -I effect in these structures since to my knowledge it can only be applied when there is a substituent (I might be wrong)...
- 371
3
votes
2
answers
896
views
Which of the following carbocations is more stable?
Which of the following carbocations is more stable?
I know two major factors in determining carbocation stability: resonance and the number of carbon atoms neighboring the positive carbon. Does the ...
user84854
2
votes
1
answer
2k
views
Hyperconjugation in bridged carbon systems
While studying about hyperconjugation, I came across the following compound which posseses one α-hydrogen (with respect to the $\mathrm{sp^2}$ hybridised carbon atom with an empty $\mathrm{p}$-orbital)...
- 131
0
votes
0
answers
2k
views
What is the order of stability of the cyclobutyl and cyclopropyl carbocations?
I know about the exceptional stability of Cyclopropylmethyl carbocation.
In some books it is given that cyclopropyl and cyclobutyl carbocations are highly unstable due to their high strain.
That ...
3
votes
0
answers
505
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 ...
- 271
1
vote
0
answers
839
views
Chirality in carbocations
The following compound is a carbocation.
Clearly, the given compound does not have any element of symmetry. The compound is non planar due to the presence of ethyl group. Thus it must be chiral. But ...
- 2,090
1
vote
1
answer
717
views
Does 2,2-dimethylpropan-1-ol give a positive Lucas test? [duplicate]
I learnt that the Lucas test involves the formation of a carbocation and it gives a positive test based on the stability of the carbocation formed, and hence primary alcohols do not show turbidity (...
- 159
3
votes
1
answer
175
views
Rearrangement considerations in feasibility of SN1 in given reactants
I have been asked to compare the feasibility of Unimolecular Nucleophilic Substitution ($\mathrm{S_N1}$) in the following question.
I have received instruction that the reaction will be feasible only ...
