Ribosylation of Adenosine: An Orthogonally Protected Building Block for the Synthesis of ADP-Ribosyl Oligomers

A method to ribosylate adenosine on the 2' hydroxyl function in an alpha-selective fashion and in good yield is presented. Protective groups chosen for the acceptor and donor used in this glycosylation not only direct alpha-selectivity but also allow the construction of a fully orthogonally protected building block for the future assembly of oligo-ADP-ribosylated peptides and proteins.