Re: What we know about Thor 2 from the Avengers...
I'm betting the whatever the confrontation in Thor 2, some of the battle will spill over into Asgard. At the end of the film, we'll see that Odin's treasure room was raided in the chaos and some items are missing, one of which is the Infinity Gauntlet.
Then, in the after-credits scene, we see Thanos laughing putting on the gauntlet.
Phase 1 >>> IM - TIH - IM2 - Thor - CA: TFA - The Avengers
Phase 2 >>> IM3 - Thor: TDW - Captain America: TWS - Guardians of the Galaxy - Avengers: Age of Ultron - Agents of SHIELD
Phase 3 >>> Ant-Man - Doctor Strange