Chapter 6, Problem 6.17P

Predict the organic product(s) of the reaction of 2-butene with each reagent.

1. (a) H₂O (H₂SO₄)
2. (b) Br₂
3. (c) Cl₂
4. (d) Br₂ in H₂O
5. (e) HI
6. (f) Cl₂ in H₂O
7. (g) Hg(OAc)₂, H₂O
8. (h) product (g) 1 NaBH₄

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Carbocation: carbon atom bears positive charged species with three bonds is called Carbocation and it plays vital intermediate in organic synthesis. Carbocation migratory aptitude is mainly depends on the stability of the carbocation. This type of carbocation undergoes inter or intra molecule reactions and it form more stable product this type of rearrangement called carbocation rearrangement.

Carbocation’s are classified in to three types as primary, secondary and tertiary depending on the number of carbon atoms which is attached to the ionized carbon.

Tertiary carbocation is more stable than secondary carbocation, secondary carbocation is more stable than the primary carbocation as shown below.

Hydration:

When alkene is undergoes hydration with water in the presence of sulfuric acid which yields the alcohol. In this reaction, the water molecule will behave like a hydrogen halide to the alkene which gives the addition product this reaction is known as a hydration reaction.

Alkene is reaction with water in the presence of sulfuric acid, first step is proton (${\text{H}}^{\text{+}}$) addition to the double bond which forms carbocation (more stable carbocation) followed by addition of hydroxide ion (${}^{\text{-}}\text{OH}$) yields alcohol as a product. The stability of carbocation is given below, Tertiary carbocation is more stable than the secondary, secondary carbocation is more stable than primary.

In hydration reaction, sulfuric acid is act as a proton donor, which is the driving force of the reaction. Hydration reaction will not go without acid (sulfuric acid).

Explanation of Solution

2-Butene reacts with water in the presence of sulfuric acid, first step is proton (${\text{H}}^{\text{+}}$) addition to the double bond which forms carbocation (more stable carbocation) followed by addition of hydroxide ion (${}^{\text{-}}\text{OH}$) yields alcohol as a product A. The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Bromination of alkenes:

Alkene undergoes bromination which yields the dibromo compound (vicinal dibromides or 1,2-dibromides).

Explanation of Solution

2-Butene undergoes bromination which yields the dibromo compound (B, vicinal dibromides or 1,2-dibromides). The addition product is a chiral molecule, it has two chiral center. Three stereoisomers are possible namely meso compound and stereoisomer.

The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Chlorination of alkenes:

Alkene undergoes chlorination which yields the dichoro compound (vicinal dichlorides or 1,2-dichlorides).

Explanation of Solution

2-Butene undergoes chlorination which yields the dichoro compound (A, vicinal dichlorides or 1,2-dichlorides). The addition product is a chiral molecule, it has two chiral center. Three stereoisomers are possible namely meso compound and stereoisomer.

The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Alkenes reaction with halogens (bromine, chlorine) in the presence of water which gives three membered ring intermediate, this three membered ring intermediate is highly reactive and it is reaction with hydroxide ion which produces chloro hydrine or bromo hydrine derivative.

Explanation of Solution

2-Butene reacts with bromine in the presence of water which gives three membered ring intermediate, this three membered ring intermediate is highly reactive and it is reaction with hydroxide ion (from water) which produces bromo hydrine derivative. The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Carbocation: carbon atom bears positive charged species with three bonds is called Carbocation and it plays vital intermediate in organic synthesis. Carbocation migratory aptitude is mainly depends on the stability of the carbocation. This type of carbocation undergoes inter or intra molecule reactions and it form more stable product this type of rearrangement called carbocation rearrangement.

Carbocation’s are classified in to three types as primary, secondary and tertiary depending on the number of carbon atoms which is attached to the ionized carbon.

Tertiary carbocation is more stable than secondary carbocation, secondary carbocation is more stable than the primary carbocation as shown below.

Markovnikov’s rule: unsymmetrical alkene reacts with hydrogen halide, halide ions goes to the more substitution position of carbon-carbon double bond which provides alkyl halides.

Explanation of Solution

The 2-butene reacts with hydrogen iodide forms carbocation intermediate, then iodine ion reacts with carbocation yields addition product B. Tertiary carbocation is more stable than secondary carbocation, secondary carbocation is more stable than the primary carbocation.

The addition product is a chiral molecule, it has one chiral center. The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Alkenes reaction with halogens (bromine, chlorine) in the presence of water which gives three membered ring intermediate, this three membered ring intermediate is highly reactive and it is reaction with hydroxide ion which produces chloro hydrine or bromo hydrine derivative.

Explanation of Solution

2-Butene reacts with chlorine in the presence of water which gives three membered ring intermediate, this three membered ring intermediate is highly reactive and it is reaction with hydroxide ion (from water) which produces chloro hydrine derivative. The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Oxymercuration:

Alkenes reaction with mercuric acetate in the presence of water, the $\text{HgOAc}$ adds to the less substituted carbon on carbon – carbon double bond and gives the corresponding organomercuric compound.

Explanation of Solution

2-Butene reacts reaction with mercuric acetate in the presence of water, the $\text{HgOAc}$ additon to the less substituted carbon on carbon – carbon double bond and gives the corresponding organomercuric compound. The reaction is shown below,

Interpretation Introduction

Interpretation:

The product of the reaction has to be predicted.

Concept interpretation:

Oxymercuration:

Alkenes reaction with mercuric acetate in the presence of water, the $\text{HgOAc}$ adds to the less substituted carbon on carbon – carbon double bond and gives the corresponding organomercuric compound. It undergoes reduction using sodium borohydride gives corresponding alcohol (B)

Explanation of Solution

2-Butene reacts reaction with mercuric acetate in the presence of water, the $\text{HgOAc}$ additon to the less substituted carbon on carbon – carbon double bond and gives the corresponding organomercuric compound. It undergoes reduction using sodium borohydride gives corresponding alcohol (B).

The reaction is shown below,