In order to access 2-deoxy-2,2-gem-difluorothionucleosides, we returned to anomeric acetate 12 and mesylate 11 to investigate nucleobase attachment. Prior reports suggested use of an anomeric mixture of 11 delivered the corresponding nucleosides as a 1/1, α/β mixture, regardless of the anomeric ratio of the starting mesyl glycoside. In order to target 4'-thiogemcitabine, silylated N 4benozyl cytosine was first glycosylated with donor 11, using TMSOTf as activator. These conditions were unsuccessful (no product was isolated) and SnCl4 was selected instead. Under these conditions the desired nucleoside was isolated, but in <10% yield. Accordingly, we switched glycosyl donor to anomeric acetate 12 and were pleased to observe an improved yield for glycosylation of silylated N 4benozyl cytosine, delivering 21 in 28% yield, with 25% of 12 recovered. Expectedly, no diastereocontrol was observed for this glycosylation; 21 was isolated as a 1.1/1 anomeric mixture, requiring subsequent separation either using fractional precipitation or preparative HPLC. Following protecting group removal, anomer 22-a was confirmed through selective 1D NOESY, where thoughspace dipolar interactions between H1 and H3 were observed. (Scheme 4 and SI Figure ). Anomer 22β was then oxidised at sulfur to afford the 4'-sulfinyl derivative of 4'-thiogemcitabine. Oxidation was confirmed through a significant downfield shift of C1' and C4' from δC 59.