Synthesis and Biological Evaluation of D- and L- Cyclohexenyl Nucleosides

Cyclohexenyl nucleosides (Figure 1) represent well-known biomimetic agents, working as bioactive nucleoside analogues, either at monomeric and oligomeric level,1 or as substrates/templates for enzymatic replication.2 These properties are due to the capacity by the cyclohexenyl ring to act as a conformational bioisostere of natural deoxyribose. Herein, the asymmetric synthesis of 2 and ent-2 (B = Pu or Py) starting from achiral cyclohexanone is reported (Figure 2). Main attention has been devoted to the key Tsuji-Trost rearrangement step of 3 and ent-3, whose unprecedented stereoconvergent outcome has been studied by chemical methods, as well as, by spectroscopic and in silico analysis. Preliminary in vitro assays against a variety of HHV infections are also presented, revealing interesting antiviral properties, especially against TK- strain