Complete the following sequence of reactions: 
SOLUTION:
A(C9H12 ) has four unsaturations, three of which are hydrogenable (double and triple bonds). The fourth non-hydrogenatable unsaturation is a cycle.
Hydration with mercuric sulfate and hydrogenation with Lindar's catalyst indicate that A has a triple bond (2 unsaturations), The other two unsaturations are a double bond and a cycle . The last reaction allows us to determine the structure of compound A. 
the compound breaks with ozone giving the expected products. Now all that remains is to find the molecule that, by reaction with H2 /Lindlar, gives the compound 
Once the structure of compound A has been determined, we complete the rest of the reactions: 
