Q.30. - Organic Chemistry

Question

Question: Draw a stepwise mechanism for the conversion of neryl diphosphate to $\mathit{\alpha }\mathbf{-}\mathit{p}\mathit{i}\mathit{n}\mathit{e}\mathit{n}\mathit{e}$ , $\mathit{\alpha }\mathbf{-}\mathit{p}\mathit{i}\mathit{n}\mathit{e}\mathit{n}\mathit{e}$ is a component of pine oil and rosemary oil.

Step-by-Step Solution

Answer

Answer

A stepwise mechanism for the conversion of neryl diphosphate to $\alpha -pinene$  is:

Step 1: Biosynthesis of terpenes and terpenoids

A diphosphate is a leaving group in the biosynthesis of terpenes and terpenoids. There are two main steps: one is forming a new sigma bond between two carbon atoms, and the other is forming a new pi bond. 

Step 2: Stepwise mechanism for the conversion of neryl diphosphate to α - p i n e n e

In the first step, diphosphate loss occurs, forming a resonance stabilized carbocation. 

In the second step, a pi bond is formed by the proton loss (with a base B), forming a $\alpha -pinene$ .

Stepwise mechanism