Used in solid-phase oligonucleotide synthesis as a phosphoramidite building block for introducing modified nucleosides into DNA strands. Its structure enables selective protection and coupling steps, making it valuable in the preparation of antisense oligonucleotides, siRNA, and other therapeutic nucleic acids. The propargyl group allows for post-synthesis modification via click chemistry, facilitating labeling or conjugation with fluorescent tags, peptides, or other functional molecules. Commonly employed in automated DNA synthesizers for research and pharmaceutical development.