Thanks guys.
I did as suggested and got a:
2x2x1-1/2" tee
1-1/2" 90 elbow
1-1/2 x 1-1/4" trap adapter (brushing?)
My problem now is that the elbow plus the trap adapter together are about an inch too long for my 2x4 stud wall (i.e. the trap adapter would stick too far out past the dry wall).
I'm trying to install a floating sink (no vanity) so I want everything to look really good under the sink as it will all be exposed.
Any suggestions? Thanks!