Synthesis of (1->3)-C and Homo(1->3)-C-Linked Imino-Disaccharides Starting from Levoglucosenone and Isolevoglucosenone

摘要

The reaction of 2,5-(benzyloxycarbonyl)imino-2,5-dideoxy-3,4-O-isopropylidene-L-ribose ((-)-15) with levoglucosenone (5) in the presence of Et_2AII gave a 3,4-dideoxy-D-glycero-hex-3-enopyranos-2-ulose derivative ((-)-16) that was converted into the (1->3)-C-linked imino-disaccharide: methylo 3,4-dideoxy-3-[(1'S)-2',5'-dideoxy-2',5'-imino-D-ribitol-l'-C-yl)-#alpha#-D-lyxo-hexopyranoside ((+)-22). The addition of benzyl alchol to isolevoglucosenone (3), followed by cross-aldol condensation with 3,6-[tert-butoxycarbonyl]imino-2,3,6-trideoxy-4,5-O-isopropylidene-L-arabino-hexonse ((+)-30) generated, after water elimination, a single enone ((+)-31) that was converted into a homo-(1->3)-C-linked imino-disaccharide: 3-deoxy-3-(1',2',3',6'-tetradeoxy-3',6'-imino-L-arabino-hexitol-1'-C-yl)-#beta#-D-galactofuranose (44).