Q56 E-b - Organic Chemistry (Mcmurry)

Question

Which of the following bases could be used to deprotonate 1-butyne?

(b) 

Step-by-Step Solution

Answer

The base of sodium methylsulfphonylmethylide will deprotonate 1- butyne.

Step 1: Dimethyl sulfoxide

Dimethyl sulfoxide is also called DMSO. It is an organometallic compound its chemical formula is (CH₃)₂SO. It is used as an organic solvent in the synthesis of various compounds. It is a polar aprotic solvent and it is a colourless liquid. It has a higher boiling point and lower melting point.

Step 2: Structure of DMSO and its applications

The structure of DMSO is:

Dimethyl sulfoxide has various applications such as:

• It is most commonly used in medicines. In analgesics, the use of DMSO is very frequent due to its property to act as an anti-inflammatory and it also act as an antioxidant.
• It is also used in many chain reactions and also used in DNA templates.

Step 3: Explanation

As we know that a base will be able to deprotonate any other acid or not it totally depends on the value of conjugate acid of that base. If the value of conjugate acid of that base will be higher it will be a weak acid and the base of that conjugate acid will be able to deprotonate any other acid. 

In the case of sodium methylsulfphonylmethylide, it is conjugate acid is dimethyl sulfoxide whose value is 35 which is higher than the value of 1- butyne i.e. value = 15.

Hence, sodium methylsulfphonylmethylide will deprotonate 1- butyne.