In this case, we assume that the starting compound is phenol which become in phenoxide due to reaction with sodium hydride. Sodium ohenoxide reacts with 3-bromo-1-propene to obtain the allyl aryl ether: allyl phenylether.
The allyl aryl ether undergoes Claisen reanrrangement when is heat between 200 and 250 celsius grades obtaining o-allyl phenol.