This boss in shadowfang keep is particularly tricky, mainly as it requires a large amount of CC on the two adds that spawn. This can be a problem for groups with little to no CC.
After a few wipes, I decided to see if I could exit the instance without dieing. I made it to the courtyard and realised that he keeps following all the way through the instance.
From this we worked out a really easy strategy. We got our tank to kite him from the room all the way back to the courtyard where the rest of the group was waiting, and killed him there. The advantage was that after we killed the adds, the new ones spawned so far away that we had killed the boss before they even reached us.
This means he can be killed effectively with no adds!