A new protecting group for the 5'-hydroxyl group having O-S single bond oxidatively cleavable under mild conditions

We developed a new protecting group, ie., cis-4-(4-methoxytrityl)sulfenyl]oxy]tetrahydrofuran-3-yl]oxycarbonyl (MTFOC), which could be removed under neutral conditions involving the oxidative removal of the MMTrS group followed by the self-cyclization of the resulting intermediate. The introduction of the protecting group into the 5-hydroxyl group of a thymidine derivative and its deprotection were studied.