Synthesis of [R-(R*,S*)]- and [S-(R*,R*)]-beta-hydroxy-3-(beta-D-ribofuranosyl)-wybutines, the most probable alternatives for the hypermodified nucleoside of rat liver phenylalanine transfer ribonucleic acid

The synthesis of the title compounds started with the Vilsmeier reaction of 3-[2,3,5-tris-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl] wye (5b) and proceeded through the Wittig reaction with (R)-N-(methoxycarbonyl)-3-(triphenylphosphonio)alaninate (4), methylation with trimethylsilyldiazo-methane, OsO4 oxidation, cyclocondensation with triphosgene, and catalytic hydrogenolysis. Chromatographic separation of the resulting diastereomeric mixture and subsequent deprotection afforded the two desired nucleosides [[R-(R*,S*)]- and [S-(R*,R*)]-2b] for the first time. (C) 1997 Elsevier Science Ltd.