Nucleoside analogues bearing a fluorine in the C2'-position have been synthesized by S2-like cyclizations of acyclic thioaminal precursors. This strategy provides access to two scaffolds, d-1',2'-cis-thiofuranosides and d-1',2'-trans-furanosides, which are difficult to generate using the standard approach for nucleoside synthesis. The addition of silylated nucleobases onto model C2-fluorinated dithioacetal substrates resulted in 1,2-syn diastereoselectivity, which is consistent with the C2-F and S-alkyl moiety being in close proximity. A new series of analogues bearing a C3' all-carbon quaternary center along with a C2'-F atom have also been synthesized using this approach and are being investigated as potential antimetabolites.

A novel thiol-functionalized PCL (PCL-HDT) was synthesized following a convenient two-step procedure. Taking advantage of the pendant thiol group, degradable elastomeric materials have been prepared from PCL-HDT by redox or thiol-ene reaction. Elastomers were characterized by HRMAS NMR spectroscopy to confirm the formation of disulfide or thioether cross-links. The thermal and mechanical properties of elastomers have been assessed by DSC, DMA and tensile tests. Disulfide containing elastomers (EM SS ) and thioether containing elastomers (EM TE ) exhibited improved mechanical properties with ultimate strains up to 220%. The stability of the mechanical properties at temperatures close to body temperature was confirmed by DMA with G 0 z 200 MPa and G 00 z 15 MPa. Finally, the reversibility of the disulfide formation and breaking has been evaluated, and confirmed the potential of these degradable elastomers as biomaterials.