Question

Draw a stepwise mechanism for the conversion of geranyldiphosphateto $\mathbf{\alpha }$-terpinene .

Short answer

Answer

Step-by-step solution

Synthesis of α-terpinene from geranyldiphosphate.

In the organic synthesis of , different steps are involved, starting with isomerization, cyclization, and nucleophilic attack. In between the mechanism, a resonance stabilized carbocation is formed.

Stepwise mechanism

• In the first step, loss of OPP occurs.
• The resonance stabilized carbocation is formed by single bond-free rotation.
• Attack of the nucleophile with diphosphate.
• The leaving group OPP is removed, and the double bond present at the other end is used for intramolecular cyclization.
• By 1,2-H shift, carbocation is stabilized, and we get the desired .

Conversion of geranyldiphosphate to$\alpha -\mathrm{terpinene}$