The coupling reactions of cyclic sulfides with a silylated pyrimidine nucleobase using a hypervalent iodine reagent were investigated. The reaction of silylated uracil with cyclic sulfide 12 using PhI![[double bond, length as m-dash]](http://www.rsc.org/images/entities/char_e001.gif)
O gave the desired β-anomer 14 in moderate yield. 4′-Thiouridine (22) was obtained by deprotection of 14.
