Application of an Enantioselective Cyclopentenone Synthesis

Significance

Analogues of nucleosides are of interest for their antiviral and antitumor activity. Previous syntheses of carbanucleosides relied on enzymatic and kinetic resolution, or on sugar chirons. Using a highly enantioselective Pauson-Khand reaction, the tricyclic intermediate 3 was obtained in enantiopure form. Subsequent straightforward transformations led to precursor 4 without loss of ee, which could be converted in two steps into either abacavir or carbovir.