Selective deacylation of peracylated ribonucleosides

Regioselective O2′,O3′‐Deacetylations of Peracetylated Ribonucleosides by Using Tetra‐n‐butylammonium Fluoride

“…Herein, we report that treatment of peracetyl ribonucleosides with tetra‐ n ‐butylammonium fluoride (TBAF) in tetrahydrofuran (THF) and water (95:5) results in the selective deacetylation of the O 2′‐ and O 3′‐positions while leaving the O 5′‐acetyl group untouched (Scheme ). Unlike previously reported procedures,7a,7b we extended the use of this TBAF‐mediated deprotection to peracetylated deoxyribonucleosides and found that the selectivity of this reaction was preserved. The use of a mild reagent such as TBAF for the selective deprotection is advantageous, as it renders the reaction with general applicability and robustness.…”

“…Although there are efficient methods for the selective deacetylation of the O 5′‐position while preserving the O 2′, O 3′ acyl groups, there are only a few protocols that can achieve the selective deacetylation of the O 2′, O 3′‐positions without affecting the O 5′‐acetate 7. Existing methodologies for the selective deacetylation of the O 2′, O 3′‐positions suffer from poor reproducibility, limited applicability, and low yields 7a,7b. Furthermore, a practical chemical method with a wide substrate scope is not available for the selective deacetylation of the O 3′‐position of peracetylated deoxyribonucleosides.…”

“…Nowak and co‐workers7b reported the use of lithium trifluoroethoxide in a selective O 2′, O 3′‐deacetylation reaction, and Rigoli and co‐workers7a used guanidinium nitrate along with sodium methoxide for the selective deacetylation of the O 2′, O 3′‐positions of peracetylated purine ribonucleosides. Nevertheless, the application of these methods to peracetylated deoxyribonucleosides resulted in a dramatic decrease in the deacetylation rate and a loss of regioselectivity for the deacetylation of the O 3′‐ versus O 5′‐position 7b.…”

Synthesis and Characterization of Oligodeoxyribonucleotides Modified with 2′-Amino-α-l-LNA Adenine Monomers: High-Affinity Targeting of Single-Stranded DNA

“…Fully protected nucleoside 6 (4.66 g, 6.76 mmol) was dissolved in solution 17 of guanidinium nitrate (4.91 g, 40.2 mmol) and NaOMe (0.24 g, 4.44 mmol) in MeOH:CH 2 Cl 2 (450 mL, 9:1, v/v). The reaction mixture was stirred at rt for 30 min at which point sat.…”

Simple method for fast deprotection of nucleosides by triethylamine-catalyzed methanolysis of acetates in aqueous medium

“…Therefore, multi-step synthesis frequently requires the introduction of protective groups and their subsequent removal. [10][11][12][13] Typical methods for removing the acetate groups in acetylated nucleosides rely on the use of methanolic ammonia, [14][15][16] metal alkoxides, [16][17][18] and hydrolytic enzymes, 19 often in good yields. Although all of the above procedures offer certain benefits, they also suffer from drawbacks such as long reaction times, high costs, the use of unstable or noxious reagents, harmful conditions, and the need for special safety precautions, which represent major disadvantages due to environmental concerns.…”