No, we can only synthesize sequences containing the four standard bases A, C, G and T.  The use of degenerate bases (R, Y, S, W, K, M, B, D, H, V, N) are not allowed. However, if you would like to have all four bases (or a subset of bases) at a given position in a fragment, you can design separate fragments, each with a different base at the site of interest.