Synthesis of novel C-4ʹ-spiro-oxetano-α-L-ribonucleosides.

The synthesis of novel C -4ʹ-spiro-oxetano- α -L- ribo nucleosides T and U in 39 and 45% overall yields have been achieved from 2′,3′,5′-tri- O -acetyl-4′- C - p- toluenesulfonyloxymethyl- β -D- xylo furanosylthymine and 2′,3′,5′-tri- O -acetyl-4′- C - p- toluenesulfonyloxymethyl- β -D- xylo furanosyluracil, respectively. Both the tosylated nucleoside precursors have been synthesized following recently developed Novozyme ® -435 catalyzed methodology. [ABSTRACT FROM AUTHOR]