Chiral pool synthesis of 4a-substituted carbocyclic cyclopentanoid nucleoside precursors, I

A suitable protected D-ribono-1,4-lactone derivative has been used for the straightforward chiral pool synthesis of cyclopentanoid nucleoside precurso rs. Thus, epoxidation followed by deoxygenation or regioselective ring open ing led to nucleoside precursors modified at the positions C(4), C(4a) and C(4,4a) as well as side-chain modified derivatives. The structures of the k ey intermediates were determined by X-ray analyses.