Q26E - Organic Chemistry (Mcmurry)

Question

The alkoxymercuration of alkenes involves the formation of an organomercury intermediate (I), which is reduced with NaBH4 to give an etherproduct. For each reaction below, predict the ether product and provide the mechanism formation.

(a) 

(b)

(c)

Step-by-Step Solution

Answer

a.

b.

c. 

Step 1: Alkoxymercuration of Alkenes

The reaction is used for the formation of ether from the alkene by reacting with the water in presence of mercury acetate formation of hydromercuration product followed by sodium borohydride for demercuration and yields ether.

Step 2: Reaction of compound A

The reactant reacts with the$\mathrm{Hg}{\left({\mathrm{CH}}_3{\mathrm{CO}}_2\right)}_2$ in presence of methanol formation of hydromercuration product occurs by breaking the double bond and addition of the $-{\mathrm{OCH}}_3$ to one carbon and mercuration occurs at another carbon

Then, followed by reaction with the sodium borohydride which leads to demercuration and addition of hydrogen occur and ether formed as below:

 

                                   Mercuration

Step 3: Reaction of compound B

The reactant reacts with the $\mathrm{Hg}{\left({\mathrm{CH}}_3{\mathrm{CO}}_2\right)}_2$ in presence of ${\left({\mathrm{CH}}_3\right)}_{2}CHOH$ product formed by mercuration that is by breaking the double bond which lead to formation of charges on carbon and  addition of the $-\mathrm{OCH}{\left({\mathrm{CH}}_3\right)}_2$ to one carbon and mercuration occur at another carbon.

Then, followed by reaction with the sodium borohydride which leads to demercuration and addition of hydrogen occur and ether formed as below:

Mercuration-Demercuration

Step 4: Reaction of compound C

1. Reaction occurs with the $\mathrm{Hg}{\left({\mathrm{CF}}_3{\mathrm{CO}}_2\right)}_2$ in presence of ethanol. Mercuration reaction occursby breaking the double bond which leads to the formation of small charges on carbon and addition of the $-{\mathrm{OCH}}_2{\mathrm{CH}}_3$ group to one carbon and mercuration reactionoccursat another carbon.

2. Then, followed by reaction with the sodium borohydride which leads to demercuration and addition of hydrogen occur and ether formed as below:

 

 

Mercuration-demercuration