Reaction of conjugated alkene with KNH2 I could not think of this reaction fitting into any of the reactions I know except the aryne mechanism. And hence I came up with the following mechanism after seeing the answer (which I've written in the picture next to question). Please tell if my proposed mechanism is correct.

Also, I am highly unsure of the fact that the last species formed will be able to extract a hydrogen atom from somewhere in the solution.

Question:



This is my proposed mechanism:





Source: Joint Entrance Exam (JEE) 1997 India
Here is a flowchart of what the commenters have stated. An &alpha;-elimination occurs stepwise 1 --> 2 --> 3. There is a phenyl migration (bridged?) to afford tolane 4. Look here for this chemistry.