We describe a long-sought route through ribose aminooxazoline to the pyrimidine β-ribonucleosides and their phosphate derivatives that involves an extraordinarily efficient photoanomerization of α-2-thioribocytidine. In addition to the canonical nucleosides, our synthesis accesses β-2-thioribouridine, a modified nucleoside found in transfer RNA that enables both faster and more-accurate nucleic acid template-copying chemistry.
Source: J. Xu, M. Tsanakopoulou, C. J. Magnani, R. Szabla, J. E. Šponer, J. Šponer, R. W. Góra and J. D. Sutherland, A prebiotically plausible synthesis of pyrimidine β-ribonucleosides and their phosphate derivatives involving photoanomerization, Nat. Chem., 2017, 9, 303–309.