Synthesis of a novel 1,2-dithianenucleoside via Pummerer-like reaction, followed by Vorbruggen glycosylation between a 1,2-dithiane derivative and uracil

The novel 1,2-dithianenucleoside was designed as a hybrid type of modification between 4'-thioribonucleoside and altritol nucleoside. The desired compound, i.e., 1-[(3R,4R,5S,6R)-4,5-dihydroxy-6-hydroxymethyl-1,2-dithianyl]uracil (20), was prepared via the Pummerer-like reaction, followed by Vorbruggen glycosylation between an appropriately protected 1,2-dithiane derivative and silylated uracil.