I\'m trying to install R using Homebrew. I ran these commands which are recommended elsewhere on SO:
brew tap homebrew/science
brew install R
I used this tutorial to install R on my mac, and it had me install xquartz and a fortran complier (gfortran) as well.
My suggestion would be to brew untap homebrew/science and then brew tap homebrew/science and try again, also, make sure you don't have any errors when you run brew doctor
Hope this helps