Tag‐Assisted Liquid‐Phase Oligonucleotide Synthesis: Toward a Convergent Approach

Although soluble support (tag)‐assisted liquid‐phase methods have found practical applications in peptide synthesis, they are still in their infancy for oligonucleotide synthesis. The development of techniques for selective tag cleavage with protective groups remaining is particularly important because such techniques are necessary to realize a convergent approach. Herein, we report an effective soluble support‐assisted liquid‐phase oligonucleotide synthesis using a novel tag that can be prepared from commercially available methyl gallate without column chromatography. Selective tag cleavages with protective groups remaining are made possible under mild reducing conditions to prepare protected fragments, which is necessary to realize a convergent approach.