Used as a phosphoramidite building block in solid-phase oligonucleotide synthesis, particularly in the preparation of modified DNA or RNA strands for research and therapeutic applications. Its adamantane-derived structure enhances stability and influences coupling efficiency during synthesis. The bis(2-cyanoethyl) group acts as a protecting group for the phosphate moiety, preventing side reactions and ensuring controlled formation of phosphodiester bonds. Commonly employed in the development of antisense oligonucleotides, siRNA, and other nucleic acid-based drugs where precise phosphate backbone modification is required.