[O] Change key binding in math mode only

[Rafael]

Hi all,

I have been writing presentations in org-mode lately with a lot of math
content. I am using org-cdlatex, and have already customized it to, say,
type R'B inside math mode to obtain \mathbb{R}. I wonder, however, if it
would be possible to make this procedure shorter, and obtain \mathbb{R}
as soon as pressing R, *but only inside math mode*. 

I guess I could approximate this with abbrevs or yasnippet, but I think
this would require an extra key besides the R, which is closer to what I
already have. 

I would appreciate any tips in this direction!

Rafael