Black 2 is a past generation game, so you cannot transfer from OR/AS to Black 2/White 2.
You can, however, transfer from Black 2 to OR by transferring the Pokemon to XY then transferring it over to OR/AS.
Plus, think about it. What would happen if you would trade a Fairy type Poke or a Mega Evolution stone over to Black 2? The game would mess up because Black 2 simply does not have the coding.
EDIT: According to WoonderWaffle, you can actually transfer Pokemon directly from Black 2 to OR.
Hope I helped!
Source: Experience / Common Knowledge