1. 2. a = Proton transfer b = Lewis acid/base c = Electrophilic addition Na CN 1. 2. conc. HBr DMF H₂C CN CH3 OH OH d = E1 Elimination e = E2 Elimination Brt The rections above involve synthesis or reactions of alcohols and ethers. Identify the mechanism by which they proceed from among the mechanisms listed. Use the letters a-g for your answers. f = SN1 Nucleophilic substitution gSN2 Nucleophilic substitution
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.
![**Chemical Reaction Mechanisms**
In this section, we explore two chemical reactions involving alcohols and ethers. Analyze the reactions and determine the mechanisms they follow, using the provided key.
**Reaction 1:**
- **Reactants:** An epoxide reacts with sodium cyanide (\( \text{Na}^+ \, \text{CN}^− \)) in the presence of DMF (Dimethylformamide).
- **Product:** A compound with a hydroxyl group (OH) and a cyanide group (CN) attached to a carbon chain.
**Reaction 2:**
- **Reactants:** An ether reacts with concentrated hydrobromic acid (HBr).
- **Products:** An alcohol and bromoalkane.
**Mechanisms Key:**
- **a** = Proton transfer
- **b** = Lewis acid/base
- **c** = Electrophilic addition
- **d** = E1 Elimination
- **e** = E2 Elimination
- **f** = \( S_N1 \) Nucleophilic substitution
- **g** = \( S_N2 \) Nucleophilic substitution
**Instructions:**
Identify which mechanism each reaction proceeds by, using the letters **a** through **g** as answers. Consider the reactants, products, and conditions detailed above.
**Mechanism Identification:**
1. [Enter answer corresponding to Reaction 1]
2. [Enter answer corresponding to Reaction 2]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff6fb7511-1856-448d-bebf-6dbc22fbc7f8%2F61df894b-a553-4f38-b76a-f486e7aa34ab%2Ffyign5l_processed.png&w=3840&q=75)
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