Novel D- and L- Cyclohexenyl Nucleosides: Asymmetric synthesis and antiviral activity

with the aim to expand the repertoire of bioactive cyclohexenyl nucleosides, we have herein explored the synthesis and the antiviral potential of novel cyclohexenyl nucleosides 4 and ent-4, lacking the OH group at C5' position and therefore being conceived as chain terminators. The synthetic path involves an enantioselective organocatalytic aldol addition of cyclohexanone4 1, to set the chirality of target nucleosides, and a stereoconvergent Tsuji-Trost rearrangement of carbonates 3, to set the relative cis configuration of the substituents. Nucleosides 4 and ent-4 are currently undergoing extensive in vitro assays aimed at determining their potential against a variety of DNA viruses and retroviruses. Preliminary tests conducted on compound 4a against CMV, VZV and HSV in HEL cells have highlighted interesting and selective antiviral properties, especially against TK-strains.