Question

3. Draw a detailed arrow-pushing mechanism for the following transformation. (4 pts) Br. Br 1. NaNH2 2. H30+

Answer 1

Here, NH₂^- from NaNH₂ behave as a base and leads to elimination twice with Br^- being the eliminating group along with H⁺​​​​​​.

The third step is an example of acid base reaction where NH₂^- deprotonates an alkynyl hydrogen.

This necessitates another additional step of acidic protonation in the final step to give the product.

Br Bn Cat. I H 'H NH₂ T ㅍ > 신 H t NH, TV 성해 (product)