Nucleoside Phosphoramidites Containing Cleavable Linkers

Phosphoramidite reagents (linker phosphoramidites) containing a cleavable 3′-ester linkage between the nucleoside and the phosphoramidite group can be used to attach the first nucleoside to a solid-phase support. Inexpensive underivatized supports such as LCAA-CPG can then be used as universal supports for oligonucleotide synthesis. No modifications to synthesis coupling conditions and no 3′-dephosphorylation are required. Only oligonucleotides with terminal 3′-OH ends are produced. Phosphoramidites containing both a succinate and a sulfonyldiethanol linkage are particularly useful and create oligonucleotides with both a 3′-OH and 5′-phosphate. In addition, by using these reagents, one oligonucleotide sequence can be added onto the 5′-end of another (tandem synthesis) to produce a string of multiple oligonucleotides linked end-to-end. Deprotection releases the oligonucleotides from each other to yield a mixture of oligonucleotides. This approach is particularly useful for making pairs of PCR primers or both strands of a double-stranded sequence in a single operation. Keywords: linker phosphoramidites; solid-phase supports; tandem oligonucleotide synthesis; 96-well plate synthesis; high-throughput synthesis; support derivatization