Chirally selective synthesis of sugar moiety of nucleosides by chemicoenzymatic approach: L- and D-riboses, showdomycin, and cordycepin.

The symmetric dimethyl esters derived from furan and dimethyl acetylenedicarboxylate was efficiently hydrolysed with pig liver esterase to yield half esters with high optical purity. Following chemical transformations afforded precursors with L-configuration, and chirality transfer through ester exchange was achieved to afford precursors with D-configuration of the sugar moiety of nucleosides. Thus, an efficient approach to L- and D-riboses, showdomycin, and cordycepin (3'-deoxy-adenosine) has been demonstrated.U