[![enter image description here][1]][1]

I have tried searching for what type of organic reaction this is in my textbooks and ended up with nothing. Thus, I could not fully understand and refer to the mechanisms that the solution has explained.


So, please tell me the types of organic reactions (i.e. name the reactions involved for me) that are involved in this question. If possible you can describe how the mechanism of this reaction. Thank You!


  [1]: https://i.sstatic.net/DWGyJ.png