A stereospecific synthesis of l-deoxyribose, l-ribose and l-ribosides

Using an inexpensive d-galactose from the chiral pool, l-deoxyribose, l-ribose and their derivatives were synthesized via mild reaction conditions. During the synthesis of l-deoxyribose, the key deoxygenation of the 2-hydroxy group of 3,5-O-dibenzyl-methyl-l-arabinofuranoside was performed by reduction of the corresponding triflate with tetrabutylammonium borohydride in high yield. During the synthesis of l-ribose, the key step of inversion of the 2-hydroxy group in the same substrate was carried out by intramolecular SN2 tandem reaction. Then the l-ribosyl donors were submitted to glycosidations according to Vorbrüggenʹs conditions to give l-ribosides (l-uridine, l-5-fluorouridine, l-iodouridine, l-thymidine, l-puridine, l-adenosine and l-guanosine) in excellent yields.