A couple things you can try.
1) Try just selecting your curved patch, open up the surface inspector ("s") and hit lightmap. Sometimes it fixes it, sometimes it doesn't. You might also try the natural setting, once again that's a hit or miss as to whether it will work.
2) Select the curved patch and the two adjacent walls and try reapplying the texture to them. I find that this works a majority of the time as it lines everything up nicely when they are all selected at once.
3) If all else fails then you can always do it the manual/hard way which is selecting your curved patch, opening up the surface inspector ("s") and manually adjusting the horizontal and vertical stretch and shift to get them to match up.
A fourth option, and one that I just remembered, is to sort of work-a-round this problem by covering up the spot where they are supposed to meet. I've done this a couple times when I just couldn't get the textures to line up. You basically just create a column or something similar at both sides where the normal wall is connected to the curved wall. This adds a little bit of realism and also covers up the fact that the textures don't align.