Synthesis of Carbocyclic Nucleosides (+)-Neplanocin A, (+)-Aristeromycin and 4'-epi-(+)-Aristeromycin from D-Fructose

D-Fructose is used as the chiral pool starting material for the stereoselective total synthesis of (+)-neplanocin A. Zinc mediated fragmentation, ring-closing metathesis and oxidative rearrangement of cyclic tertiary allylic alcohol are used as the key steps in achieving the synthesis of key carbocylic intermediate. Further, stereoselective total synthesis of 4'-epi-(+)-aristeromycin and the conversion of (+)-neplanocin A to a mixture of (+)-aristeromycin and 4'-epi-(+)-aristeromycin are described.