An activator-free method for the synthesis of nucleotide 5'-5' triphosphate mRNA capping agent
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Updated: Oct 31, 2026

Chemical Triphosphorylation of Oligonucleotides
Published on: June 2, 2022
Eric Tam1, Viktor Barát1, Tzuen Yih Saw2
1Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR) 8 Biomedical Grove, #07-01 Neuros Building Singapore 138665 Republic of Singapore lim_yee_hwee@a-star.edu.sg.
Abstract:
The traditional synthesis of nucleotide 5'-5' triphosphate linkages involves a "2 + 1" phosphate coupling mediated by a large excess of metal salts, where the salt removal is a labor and waste-intensive step. We have omitted the metal salts from this reaction by modulating the solubility and reactivity of the monophosphate coupling partner using a precise combination of the reaction solvent and the paired cation. This resulted in simplified downstream purification, where the amount of waste generated was reduced by over 60% throughout the whole process. We have demonstrated this synthetic approach on ARCA, an mRNA 5'-capping agent. Both the chemical purity of the product and its performance in mRNA was comparable to commercial samples.
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