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.
![## Hydroboration-Oxidation Reaction
### Task:
Draw the major product of this reaction. Ignore inorganic byproducts.
### Reaction Details:
**Reactant:**
- Cyclohexene with an ethylidene side chain.
**Reagents:**
1. \( \text{BH}_3 - \text{THF} \) (Borane - Tetrahydrofuran)
2. \( \text{H}_2\text{O}_2, \text{NaOH} \) (Hydrogen Peroxide, Sodium Hydroxide)
[Select to Draw]
In this reaction, the Hydroboration-Oxidation mechanism is used to convert an alkene to an alcohol. Here is a brief overview of the steps:
1. **Hydroboration:** \( BH_3 \) (in THF) adds across the carbon-carbon double bond (C=C) in an anti-Markovnikov fashion, leading to the formation of a trialkylborane intermediate.
2. **Oxidation:** The trialkylborane intermediate is then oxidized by \( \text{H}_2\text{O}_2 \) (in alkaline conditions), resulting in the formation of an alcohol. The hydroxyl group (-OH) is added to the carbon that would be less substituted after hydroboration.
### Concept Check:
- Anti-Markovnikov addition implies that the hydroxyl group will attach to the less substituted carbon.
- The reaction proceeds through the formation of an organoborane intermediate, which is then converted to an alcohol.
### Graphical Representation:
**Initial Structure:**
- The starting material is cyclohexene with an additional ethylidene group connected.
**Intermediate:**
- Formation of trialkylborane is not shown but important to understand.
**Final Product:**
- You are expected to draw the final structure of the major product in the dashed box below.
[Select to Draw]
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This explanation should guide you in understanding the reaction mechanism and expected products, allowing you to properly draw the major organic product formed through the specified steps.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F44572439-aee9-40a4-8ec4-b1e043de89f6%2Fbe1d3cc5-35be-4724-98e9-adb84017f067%2Fd75jyug_processed.jpeg&w=3840&q=75)
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