A versatile strategy for oligonucleotide functionalization via on-support phosphitylation

Area of Science:

• Biochemistry
• Medicinal Chemistry
• Molecular Biology

Background:

• Chemically modified nucleic acids, including antisense oligonucleotides (ASOs), small interfering RNA (siRNA), and CRISPR guide RNA, are crucial for treating genetic disorders, viral infections, and cancer.
• Current therapeutic applications are constrained by challenges in intracellular delivery and targeting, necessitating advanced chemical functionalization methods.

Purpose of the Study:

• To present a streamlined and versatile method for the site-selective chemical modification of synthetic oligonucleotides.
• To enhance the functionalization capabilities for therapeutic oligonucleotide development.

Main Methods:

• Developed an in situ phosphoramidite generation strategy on solid-supported oligonucleotides.
• Utilized inexpensive, bench-stable alcohols or nucleosides for modification.
• Demonstrated compatibility with various functional groups, including azides, amines, and thiols.

Main Results:

• Achieved site-selective modification at the 5' and 3' termini, as well as internal sites of oligonucleotides.
• Demonstrated high coupling efficiency and broad functional-group compatibility.
• Showcased efficient recovery of excess reagents, indicating a robust and scalable process.

Conclusions:

• The described methodology provides a robust platform for advancing and diversifying therapeutic oligonucleotide modification.
• This approach simplifies the chemical functionalization of oligonucleotides, potentially overcoming key delivery and targeting limitations.