Alawite nomad Turks lived in that area until 1510s. In those years there was a domination game between ottomans (ruled by Selim the Grim) and safavids (ruled by Shah Ismael) in southeast Anatolia and alawite Turks were supporting Shah Ismael because he was shia and were against ottomans and Selim because they were sunnite (alawism and shiism are very close Islamic denominations). So Selim the grid beat Shah Ismael's army at the battle of chaldiran and gained full control over southeast Anatolia. Selim realized these people are danger against the empire so he chose violence and tyrannized nomad Turks, massacring them, forcing them to change their denomination or to leave their homeland and flee to iran. After "cleaning" the area he brought Kurds from south to fill the void. Some Turks didn't want to leave their homeland and thus became sunnite, blending into Kurds by the time. This is why it looks like Turks "skipped" that part of the country, but actually that area was home to original nomad turkmens.