First Synthesis of (−)-Neplanocin C

(−)-Neplanocin C (4), a minor component of the neplanocin family of antibiotics and a lead drug for the design of several conformationally constrained nucleosides analogues, was enantioselectively synthesized starting from d-ribono-1,4-lactone via a convergent approach in twelve steps. The proton NMR spectrum of 4 was in agreement with the corresponding natural product. Calculated coupling constants obtained from ab initio molecular modeling studies and from previously published X-ray structure of neplanocin C also corresponded to the spectroscopic data.