Allyl group as a protecting group for internucleotide phosphate and thiophosphate linkages in oligonucleotide synthesis: Facile oxidation and deprotection conditions

[GRAPHICS] The allyl group, which serves as a protecting group for an internucleotide bond for both phosphates and phosphorothioates, can be easily removed by go od nucleophiles under weakly basic or neutral conditions. For a practical s ynthesis on solid support, camphorsulfonyloxaziridine was used as the oxidi zing agent for synthesizing DNA, while the Beaucage reagent was used for pr eparing phosphorothioate oligomers, Both types of oligonucleotides were eas ily deprotected by concentrated ammonium hydroxide containing 2% mercaptoet hanol.