Fares from Europe to South America in that price range have been around for quite some time. I regularly fly (STR, AMS, or CDG) - GRU in J for between $1800 and $2500, depending on the season, with two long (as in months, since I live there) stopovers in the US. The fares are sometimes hard to find, I usually find them through multi city search on delta.com, often the low fare shows up only when chosing the last leg..