Efficient diastereoselective synthesis of a new class of azanucleosides: 2'-homoazanucleosides.

Azanucleosides, sugar-modified nucleoside analogues containing a 4' nitrogen atom, have shown a lot of therapeutic potential, e.g. as anti-cancer and antiviral agents. We report the synthesis of a series of 2'-homoazanucleosides, in which the nucleobase is attached to the 2'-position of the pyrrolidine ring via a methylene linker. A suitable orthogonally protected iminosugar was synthesized by ring closing metathesis and dihydroxylation as key steps and further converted to a series of 8 nucleoside analogues through Mitsunobu reaction with suitably protected nucleobases. The 5' position of the adenine analogue was then further derivatized with thiols to afford 2 additional compounds. The final compounds were evaluated for biological activity.