Used in the synthesis of modified oligonucleotides for therapeutic and diagnostic applications. Enables site-specific attachment of cholesterol derivatives through solid-phase synthesis, enhancing cellular uptake and stability of nucleic acid constructs. Particularly valuable in developing antisense oligonucleotides, siRNA, and aptamers with improved pharmacokinetic properties. The carbamoyl group supports conjugation while maintaining biocompatibility, and the phosphoramidite group allows efficient incorporation into DNA/RNA strands during automated synthesis.