D-?Ribitol, 1,?4-?anhydro-?5-?O-?[bis(4-?methoxyphenyl)?phenylmethyl]?-?2-?O-?methyl-?, 3-?[2-?cyanoethyl N,?N-?bis(1-?methylethyl)?phosphoramidite] [ 1470023-72-3 ]