Novel Galf-disaccharide mimics: synthesis by way of 1,3-dipolar cycloaddition reactions in water
摘要:
Galactofuranose-disaccharide analogues incorporating a 1,4-dideoxy-1,4-imino-D-galactitol moiety were obtained by 1,3-dipolar cycloadditions of a galacto-configured cyclic nitrone with arabino- or galacto-furanosides carrying a C-vinyl or O-allyl substituent. Remarkably, the cycloadditions could be performed highly efficiently and stereoselectively in water using unprotected nitrone and sugar-derived dipolarophile as reaction partners. The resulting pseudo-disaccharides are analogues of the Galf-Galf motifs found in mycobacterial cell-wall glycans and therefore constitute mimics of the acceptor substrates of mycobacterial Galf-transferases. (C) 2008 Elsevier Ltd. All rights reserved.