The Fluoride Cleavable 2-(Cyanoethoxy)Methyl (CEM) Group as Reversible 3′-O-Terminator for DNA Sequencing-by-Synthesis—Synthesis, Incorporation, and Cleavage

A new and promising sequencing technology called sequencing-by-synthesis (SBS) enables fast determination of DNA sequences. 2′-Deoxynucleotides containing the (2-cyanoethoxy)methyl (CEM) group at the 3′-O-position are potential reversible terminators for the SBS technology. Herein we describe the synthesis, the incorporation by several polymerases, and the cleavage of this 3′-O-blocking group using 3′-O-CEM-thymidinyl-5′-O-triphosphate 7 as an example.