It has been the dream of every Russian Tsar since Peter the Great to take Constantinople the Bosphorus and the Dardenelles. Putin is no different.
The Soviets also wanted to take Turkey.
Putin has already threatened to stage a coup in Turkey and install a puppet government. So, his war in Syria serves a two-fold purpose (at least): prop up his puppet regime in Syria to keep the Iran-Syria-Hezbollah axis alive, and bait Turkey into actions that will justify a Russian takeover.
Once those are accomplished, I believe Israel is the next target.
It has been the dream of every Russian Tsar since Peter the Great to take Constantinople the Bosphorus and the Dardenelles. Putin is no different.
+1