Reactive Intermediates
In chemistry, reactive intermediates are termed as short-lived, highly reactive atoms with high energy. They rapidly transform into stable particles during a chemical reaction. In specific cases, by means of matrix isolation and at low-temperature reactive intermediates can be isolated.
Hydride Shift
A hydride shift is a rearrangement of a hydrogen atom in a carbocation that occurs to make the molecule more stable. In organic chemistry, rearrangement of the carbocation is very easily seen. This rearrangement can be because of the movement of a carbocation to attain stability in the compound. Such structural reorganization movement is called a shift within molecules. After the shifting of carbocation over the different carbon then they form structural isomers of the previous existing molecule.
Vinylic Carbocation
A carbocation where the positive charge is on the alkene carbon is known as the vinyl carbocation or vinyl cation. The empirical formula for vinyl cation is C2H3+. In the vinyl carbocation, the positive charge is on the carbon atom with the double bond therefore it is sp hybridized. It is known to be a part of various reactions, for example, electrophilic addition of alkynes and solvolysis as well. It plays the role of a reactive intermediate in these reactions.
Cycloheptatrienyl Cation
It is an aromatic carbocation having a general formula, [C7 H7]+. It is also known as the aromatic tropylium ion. Its name is derived from the molecule tropine, which is a seven membered carbon atom ring. Cycloheptatriene or tropylidene was first synthesized from tropine.
Stability of Vinyl Carbocation
Carbocations are positively charged carbon atoms. It is also known as a carbonium ion.
![**Transcription and Explanation for Educational Website**
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**Question 3:** Add curved arrows to the following reactions to indicate the flow of electrons.
**a.**
\[
\begin{align*}
&\begin{array}{c}
\stackrel{..}{O} \\
| \\
CH_3
\end{array}
+ H-Cl \rightleftharpoons
\left( \begin{array}{c}
\stackrel{H}{|} \\
\overset{+}{\overset{O}{/}} \\
CH_3
\end{array} \right)
\rightleftharpoons
\begin{array}{c}
.. \, \overset{-}{\colon}Cl \, .. \\
| \\
CH_3CH_2-Cl
\end{array}
\end{align*}
\]
**Explanation:**
The curved arrows should show the electron pair from the oxygen atom attacking the hydrogen of HCl, forming an oxonium ion. Subsequently, the Cl⁻ ion should attack the carbon to form an ether.
**b.**
\[
\begin{align*}
CH_3-CH^+-CH_3 + \overset{..}{\underset{..}{Cl^-}}
&\rightarrow
CH_3-CH(Cl)-CH_3
\end{align*}
\]
**Explanation:**
Show the electron pair from the chloride ion attacking the carbocation, forming 2-chloropropane.
**c.**
\[
\begin{align*}
CH_3-CH=CH_2 + H-Cl
&\rightarrow
CH_3-CH^+-CH_2(Cl) + \overset{..}{\underset{..}{Cl^-}}
\end{align*}
\]
**Explanation:**
Curved arrows should indicate the pi electrons of the double bond attacking the hydrogen of HCl. This forms a secondary carbocation, which is then attacked by the chloride ion to yield the product.
**Note:** Understanding the movement of electrons shown by curved arrows is crucial for predicting the outcomes of organic reactions. Each step should consider the charges and the stability of intermediates formed during the process.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fb35fb7dd-68df-4d1d-8b67-4ee32796d12d%2F15026c3f-1852-4e97-8b60-8d4841736704%2Fat9sl7a_processed.png&w=3840&q=75)
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