1,2-Di-O-acetyl-5-O-benzoyl-3-deoxy-L-erythro-pentofuran ose, a convenientprecursor for the stereospecific synthesis of nucleoside analogues with the unnatural beta-L-configuration

The title compound 1,2-di-O-acetyl-5-O-benzoyl-3-deoxy-L-erythro-pentofuran ose (5), a useful precursor for the stereospecific synthesis of beta-L-nucl eoside analogues as potential antiviral agents, has been synthesised by a m ulti-step reaction sequence from L-xylose with a 38% overall yield. The pre paration involved conversion of L-xylose to 1,2-O-isopropylidene-alpha-L-xy lofuranose which, upon selective 5-O-benzoylation and subsequent radical de oxygenation, provided the protected 3-deoxy sugar derivative. Finally, clea vage of the acetonide group gave the resulting 5-O-benzoyl-3-deoxy-L-erythr o-pentose which was acetylated to afford crystalline alpha,beta-5. (C) 2000 Elsevier Science Ltd. All rights reserved.