The condensation of the chiral dioxolane (I) with 5(E)-(2-bromovinyl)uracil (II) by means of Tbdms-OTf and lutidine gives the silylated nucleoside (II), which is purified by chromatography. Finally, this compound is deprotected by means of TBAF in acetonitrile. (1,2)
Hydrogenolysis of benzyl ether (I) in the presence of Pd/C afforded dioxolane alcohol (II), which was acetylated with Ac2O and pyridine to give diacetate (III). Subsequent condensation of (III) with the silylated (2-bromovinyl)uracil (IV) led to a diastereomeric mixture of nucleosides (V) and (VI). After chromatographic isolation of the desired isomer (V), hydrolysis of the acetate ester using K2CO3 in MeOH yielded the title compound.
The condensation of the chiral dioxolane (I) with 5(E)-(2-chlorovinyl)uracil (II) by means of Tbdms-OTf and lutidine gives the silylated nucleoside (II) that is purified by chromatography. Finally, this compound is deprotected by means of TBAF in acetonitrile.
The condensation of the chiral dioxolane (I) with 5(E)-(2-iodovinyl)uracil (II) by means of Tbdms-OTf and lutidine gives the silylated nucleoside (II), which is purified by chromatography. Finally, this compound is deprotected by means of TBAF in acetonitrile.