Polymer-bound oxathiaphospholane: A solid-phase reagent for regioselective monothiophosphorylation and monophosphorylation of unprotected nucleosides and carbohydrates

[GRAPHICS] Two polymers bound to N,N-diisopropylamino-1,3,2-oxathiaphospholane were reacted with unprotected carbohydrates and nucleosides in the presence of 1H-tetrazole, followed by oxidation with tert-butyl hydroperoxide or sulfurization with Beaucage's reagent. The 1,3,2 oxathiaphospholane ring-opening with 3-hydroxyproplonitrile, followed by treatment with DBU, afforded the corresponding monophosphate and monothlophosphate derivatives, respectively, through the elimination of polymer-bound ethylene episulfide. Reactions using this strategy offer the advantages of high regioselectivity, monosubstitution, and facile isolation and recovery of products.