draw the major organic product of the following reaction sequence.

Question 1

Question 2

Question 3

Question 4

Answer to question 1

Answer to question 2

Answer to question 3

Step 1

The major organic product of the following reaction sequence is to be drawn.

Step 2

It occurs in two steps-

In first step, the mercuric acetate reacts with alkene leading to addition of acetoxymercury (HgOAc) groups and hydroxyl (OH) group across a double bond. This step follows markovnikov’s rule (the hydroxyl group is added to the more substituted carbon atom).

In second step, the adduct product of 1st step is reduced by NaBH4. In demercuration, the acetoxymercury group is replaced with a hydrogen atom.

Step 3

Therefore, the major organic product of the given reaction would have

OH group attached to a  carbon 2 atom forming secondary alcohol.

Step 4

Thus, the final product obtained is Butan-2-ol.

Answer to question 4

Step 1: Interpretation

The given reagents are:

RCO3H    —- Peroxycarboxylic acid —– Used for formation of epoxides

MeMgBr —- Grignard reagent        —- Used for introduction of Alkyl or aryl moiety to the substrate.

H2O        —- Water                          —- used for hydrolysis

The reagent RCO3H is used to introduce epoxide at the double of the molecule as the oxygen attached to the hydrogen of RCO3H is having a partial positive charge on it. So it will act as a electrophile.

Structure of RCO3H :

Step 2: Reaction of alkene with per oxy carboxylic acid

The reaction is:

This reaction is a concerted process in which double bond acts as nucleophile and will attack the partially positive charged oxygen which is attached to hydrogen as it act as electrophile. Simultaneous hydrogen is abstracted by the carbonyl pie bond, a carbonyl is formed by partially negative charged oxygen as the bond breaks between two oxygen atoms resulting in formation of epoxide and a carboxylic acid.

Step 3: Reaction of formed epoxide with Grignard reagent

A Grignard reagent consists of a nucleophilic organic moiety which attacks the carbon that is more stable as a carbocation as the nucleophilic attack leads to formation of a negative charge on the molecule that must be stable among all the other possibilities.

Reaction of Epoxide with MeMgBr (Grignard reagent) :

The attack of methyl group takes place at secondary carbon as the anion is primary which is more stable compared to the attack of methyl group on primary carbon that form a secondary anion which is less stable.

Therefore the product formed in major in the first reaction.

Step 4: Hydrolysis of major product in the above reaction

Hydrolysis of major product leads to formation of hydroxyl group as below:

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