[sumdood5]

I am having difficulty understanding how to understand and draw frontier molecular orbital. I was wondering if someone can help and also try to walk me through this following problem as well?

I have attached an image but I will also post a picture of the problem here just in case: http://postimg.org/image/f9i5ztu3h/

The second electrophile that should be formed is the center carbon triple bonded to the oxygen. I think that is right because that will allow me to kick off the the ALCL4 (-) group. I guess my problem is more of a visual understanding of the problem in order to see which orbitals are directly interacting. The lone pair on the chlorine will interact with the empty orbital of the Al forming that sigma bond. So, if I were to draw a FMO diagram, would the two electrons from the chlorine be added to the bonding level in order to form the sigma bond with the Al? How would I approach the next step in order to form the other electrophile?

Thank You