The synthesis and properties of 5-hydroxymethyldeoxyuridine (6) and its α-anomer 7 are described. Treatment of 5-hydroxymethyluracil (2) with trimethylchlorosilane in the presence of triethylamine gave 2,4,5-tris(trimethylsilyl)-5-oxymethyluracil (3) in excellent yield (92%) which, upon condensation with 3,5-di-(O-p-toluoyl)-2-deoxy-D-ribofuranosyl chloride in acetonitrile at room temperature, furnished an anomeric mixture of substituted nucleosides β-anomer (4) and α-anomer (5) in high yield 90% (by a fusion method (12) yield of blocked nucleosides was 70%). Compound 4 was the major product formed by both methods and was recovered as a crystalline solid in high yield. However, condensation of 3 with chlorosugar in benezene with mercuric chloride as a catalyst at room temperature gave a mixture of protected nucleosides; the amount of 5 formed was appreciably higher (34%) and was isolated as a microcrystalline solid from mother liquors in low yield (without the catalyst nucleosides were formed in low yield 30%). Removal of the blocking groups by alcoholysis gave 6 and 7 in high yields. The structure was confirmed by n.m.r. studies, u.v. and i.r. absorption spectra, elemental analysis, and by conversion of 4 to β-thymidine (8).