(A) new, versatile protection of nucleic acids using arylsulfenyl chlorides

Abstract

Developments of efficient protecting groups are very important in the synthesis of oligonucleotides and sugar modifications. The arylsulfenates have been found to be versatile blocking groups for the hydroxyl functions such as sugar hydroxyls and for the amide moieties in nucleotides. 2``,3``,5``-Tri-O-acetyluridine or purine derivatives were treated with sodium hydride in acetonitrile or tetrahydrofuran at 20$^\circ$C and then followed by the addition of arylsulfenyl chlorides to result in the corresponding arylsulfenates at 4-position or at 6-position of purine selectively in excellent yields (90-95\%). Deblocking was easily performed at 20$^\circ$C by treating with thiophenol or with silica gel.