It doesn't make any difference what the color of the first roll is.
The second roll must have a different color than the first roll; this will occur 4 out of 6 times, or 2/3.
The third roll must have the last color; this will occur 2 out of 6 times, or 1/3.
Multiplying he possibilities together, we get: 1 x (2/3) x (1/3) = 2/9.