Used in solid-phase oligonucleotide synthesis to introduce glycol nucleic acid (GNA) monomers with isobutyl protection into DNA/RNA strands. Enables the construction of GNA-modified sequences for studying nucleic acid stability, hybridization behavior, and potential antisense or diagnostic applications. The phosphoramidite group allows for efficient coupling under standard synthesis conditions, while the (S)-configuration ensures stereochemical consistency in the backbone. Preferred in research settings exploring synthetic genetics and nucleic acid analogs with enhanced biostability.