Branched-chain sugars. Part 14. Synthesis of new branched-chain cyclitols having myo- or scyllo-, and muco-configuration from 3-O-benzyl-5,6-dideoxy-5-C-(1,3-dithian-2-yl)-6-nitro-L-idofuranose and -D-glucofuranose

Abstract

Michael addition of 2-lithio-1,3-dithian to 3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-6-nitro-α-D-xylo-hex- 5-enofuranose (1) gives 3-O-benzyl-5,6-dideoxy-5-C-(1,3-dithian-2-yl)-1,2-O-isopropylidene-6-nitro-β-L-idofuranose (2) and -α-D-glucofuranose (3) in the ratio 4 : 3, respectively. Removal of the isopropylidene group and intramolecular cyclization in weak basic conditions gives branched-chain cyclitols having myo- or scyllo-configuration from (2) and muco-configuration from (3). The mechanism of cyclization is discussed.