Used in solid-phase oligonucleotide synthesis as a phosphoramidite building block for incorporating modified nucleosides into DNA strands. The benzamido and methoxyethoxy groups provide steric protection and enhance solubility during synthesis. The diisopropylphosphoramidite group enables efficient coupling to the growing oligonucleotide chain on a solid support. The bis(4-methoxyphenyl)(phenyl)methoxy group acts as a protecting group for the 5'-hydroxyl, allowing selective deprotection under mild acidic conditions. The 2-cyanoethyl group stabilizes the phosphate linkage during synthesis and is removed during final deprotection. Commonly used in the preparation of antisense oligonucleotides, siRNA, and diagnostic probes where precise modification is required for stability or binding affinity.