NAV is pretty poor in this car. Or maybe I am spoiled by my Android phone and Google maps where voice commands of a location work flawlessly (hit the Navigation arrow on the phone, select the microphone picture that says "speak destination", say "Burger King" and bingo, it shows a list of the nearest locations sorted by distance).
BMW NAV.... forget it. You have to know the street address, and enter / speak that.
Mind you, I had a Honda Ridgeline (2010) that had a NAV that worked similar to Google - just say the name and it would try to interpret it (and the NAV screen was touch screen).
I don't know if BMW used the same crappy NAV on all their vehicles, but I would be pretty let down if I had a 6 or 7 series that had such a poor system.
I've resorted to what someone else said, have my phone look up the address, and then enter the address into the NAV in the car. That's pretty lame.