Russia, Turkey and Kurdish Issue
Turkey is reaching out to Russia now because of two situational impulses – the need to hedge against what is obviously a failed bid to enter the EU and to defend against the US' plans for creating a "federalized" Kurdish-led state in Syria.
The Brexit crushed Erdogan's hopes of ever clinching a visa-free travel arrangement with the EU (i.e. the institutionalizations of the Immigrant Crisis), and the US' persistent efforts to help midwife the "geopolitical Israel" of "Kurdistan" in the heart of the Mideast is a long-term existential threat to the Turkish state.
Having set the stage for a potential re-pivot over a month ago with the replacement of Davutoglu with Yildirim (and preparing the former to be the "fall man" for shooting down the Russian anti-terrorist jet over Syria), Erdogan played his cards right in crafting a "geopolitical insurance policy" just in case the US and EU turned against him.
What the Turkish leader is offering his Russian counterpart is to unfreeze the Balkan Stream pipeline in exchange for the lifting of Moscow's restrictive economic measures against Turkey. The country also badly needs Russian tourists to rejuvenate it's ruined economy, which is increasing civil dissent against the government.
As for Russia's interests, it wants to manage Turkey and capitalize off of its leadership's disappointment with the EU and the US. There's even a chance that Turkey might redirect its focus towards the East, namely through a potential SCO membership bid and/or a negotiated free trade agreement with the Eurasian Union. Both of these would be beneficial for Russia's grand strategy of dismantling the unipolar world order.
As it relates to the Kurdish issue, Ankara wants Moscow to resolutely support the Syrian authorities in what looks to be their imminent post-Daesh liberation campaign against the illegal YPG-occupied "federal" (internally partitioned) areas. Turkey will not militarily invade Syria to stop this destructive American project, so it's depending on Russian air and special forces support to aid the Syrian Army during a forthcoming operation.
Turkey's main concession is that it will implicitly accept President Assad's leadership (despite whatever public "face-saving" statements the Turkish government makes about this) so long as the Syrian Arab Army succeeds in squashing the US' second "geopolitical Israel" vision of "Kurdistan" with Russian assistance.
On a final note pertaining to the "Kurdistan" issue, there's a medium-term chance of Syria, Iran, Iraq, and Turkey – all of which are currently challenged by militant Kurdish separatism – coordinating together under Russian "Lead From Behind" supervision in destroying this militant menace and enforcing the disarmament of pro-American Kurdish separatism groups in the region.
Should this possible eventuality play out, then it could lay the structural foundation for a post-Daesh Mideast version of the Congress of Vienna.