Protocol for producing phosphoramidate using phosphorus fluoride exchange click chemistry
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Updated: Jul 5, 2025

Chemical Triphosphorylation of Oligonucleotides
Published on: June 2, 2022
Joshua A Homer1, Shoujun Sun1, Rebecca A Koelln1
1Cancer Center, Cold Spring Harbor Laboratory, Cold Spring Harbor, 1 Bungtown Road, NY 11724, USA.
Abstract:
Phosphorus fluoride exchange (PFEx) is a catalytic click reaction that involves exchanging high oxidation state P-F bonds with alcohol and amine nucleophiles, reliably yielding P-O- and P-N-linked compounds. Here, we describe steps for preparing a phosphoramidic difluoride and performing two sequential PFEx reactions to yield a phosphoramidate through careful catalyst selection. We then detail procedures for handling and quenching potentially toxic P-F-containing compounds to ensure user safety when conducting PFEx reactions. For complete details on the use and execution of this protocol, please refer to Sun et al.1.
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