Carbocyclic analogs of nucleosides. Part 2. . Synthesis of 2′,3′‐dideoxy‐5′‐homonucleoside analogs

A set of derivatives of cyclopentaneacetic acid cis ‐substituted at position 3 by nucleoside bases (both purines and pyrimidines) were prepared and characterized (see 11, 14 , and 23a, b; Schemes 2–4 ). These molecules are carbocyclic analogs of 2′,3′‐dideoxy‐5′‐homonucleosides. In this synthesis, the skeleton was constructed from norbornanone and a novel method based on Mitsunobu chemistry used for the introduction of nucleoside‐base substituents. The scope of this method was further explored via the preparation of a cyclobutyl analog of dideoxyguanosine (see 17 , Scheme 3 ).