Studies on the Stereoselective Synthesis of Deuterated D‐Ribose Derivatives

In view of the importance of the site‐specific substitution of the H‐atom by its stable isotope ²H in a stereoselective/stereospecific manner at the pentose sugar residue, decreasing the spectral overcrowding in various regions of 1D and 2D homo‐ and heteronuclear correlation spectra of oligo‐DNA and ‐RNA, there is always a need for the development of new methods for the incorporation of ²H at different sites of a ribose. High‐yielding multistep syntheses of C(2)‐, and (5R)‐ and (5S)‐3,5‐deuterated ribose derivatives have been envisaged for the application of site‐specific incorporation of multilabeled nucleosides into oligomers to facilitate their structure elucidation by NMR spectroscopy. All syntheses started from D ‐glucose after proper derivatization. In the case of C(2), >97 atom‐% isotope was incorporated, employing an inversion of the configuration at C(2) as the key reaction. For C(5), two different routes were envisaged: on the one hand, deuterated achiral reagent was treated with a conformationally locked sugar moiety 15 , while, on the other, chiral protonated sources were used to transfer the H‐atom to a C(5)‐deuterated aldehyde 18 . In all cases, enantiomeric and isotopic purities were found to be as high as >97% as determined by NMR spectroscopy.