A new protecting group ‘3′,5′-O-sulfinyl’ for xylo-nucleosides. A simple and efficient synthesis of 3′-amino-3′-deoxyadenosine (a puromycin intermediate), 2,2′-anhydro-pyrimidine nucleosides and 2′,3′-anhydro-adenosine

We developed a new protecting group, the cyclic sulfite for the protection of the 3′,5′-dihydroxy group of nucleosides. Seven cyclic sulfites, 4a–c, 5a–b, and 6a–b were prepared in high yields from the corresponding xylo-uridines 1 and 2, and xylo-adenosines 3 with thionyl chloride, respectively. Synthesis of the puromycin intermediate 8 was carried out by deprotection of the sulfite moiety through an intramolecular cyclization of the 2′-α-carbamate 7.