Chlorodifluoromethyl-substituted monosaccharide derivatives--radical activation of the carbon-chlorine-bond.
The dithionite-mediated addition of BrCF(2)Cl to 3,4-di-O-pivaloyl-D-xylal (1) generated preferably 1-CF(2)Cl-substituted products, that is, (2-bromo-2-deoxy-3,4-di-O-pivaloyl-beta-D-xylopyranosyl)-chlorodifluoromethane and (2-deoxy-3,4-di-O-pivaloyl-beta-D-threo-pentopyranosyl)-chlorodifluoromethane. Selected chlorodifluoromethyl-substituted monosaccharide derivatives were hydrodechlorinated or alkylated at the CF(2)Cl-group using tin reagents under radical reaction conditions. Thus, hydrodechlorinations of (2,3,4-tri-O-acetyl-6-deoxy-alpha-L-galactopyranosyl)-chlorodifluoromethane and of methyl 3,4-di-O-acetyl-2-C-chlorodifluoromethyl-2,6-dideoxy-alpha/beta-L-glucopyranoside are reported using tri-n-butyltin hydride initiated by AIBN. UV-initiated allylations are reported for reactions of (2-deoxy-3,4-di-O-pivaloyl-beta-D-threo-pentopyranosyl)-chlorodifluoromethane, (2,3,4-tri-O-acetyl-6-deoxy-alpha-L-galactopyranosyl)-chlorodifluoromethane, 1,3,4,6-tetra-O-acetyl-2-C-chlorodifluoromethyl-2-deoxy-alpha-D-glucopyranose, 1,3,4,6-tetra-O-acetyl-2-C-chlorodifluoromethyl-2-deoxy-alpha-D-mannopyranose and methyl 3,4-di-O-acetyl-2-C-chlorodifluoromethyl-2-deoxy-alpha/beta-D-rabinopyranoside with allyltri-n-butyltin.
Wegert
Anita
A
Institut für Chemie, Organische Chemie, Universität Rostock, Albert-Einstein-Strasse 3a, D-18059 Rostock, Germany.
Hein
Martin
M
Reinke
Helmut
H
Hoffmann
Norbert
N
Miethchen
Ralf
R
D002244:Carbon / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D005617:Chlorofluorocarbons, Methane / Q000737:chemistry*; D008958:Models, Molecular; D009005:Monosaccharides / Q000737:chemistry*; D014220:Trialkyltin Compounds / Q000737:chemistry
D005617:Chlorofluorocarbons, Methane; D009005:Monosaccharides; D014220:Trialkyltin Compounds; D002713:Chlorine; D002244:Carbon