title: FeCl3 mediated arylidenation of carbohydrates.
abstract: Glycosides and thioglycosides based on monosaccharides in reaction with benzaldehyde dimethylacetal or p-methoxybenzaldehyde dimethyl acetal undergo FeCl(3)-catalyzed (20 mol%) regioselective 4,6-O-arylidenation producing the corresponding acetals in high yields. FeCl(3) also mediates acetalation of glycosides and thioglycosides of cellobiose, maltose, and lactose affording the corresponding 4',6'-O-benzylidene acetals, which were isolated after their acetylation in situ with acetic anhydride and pyridine. The combined yields (two steps) of these final products are also high (61-84%). The procedure is applicable to a wide variety of functional groups including -OBn.
authors.affiliation: Department of Chemistry, Jadavpur University, Kolkata 700 032, India.
authors.forename: Nabamita
authors.initials: N
authors.lastname: Basu
authors.forename: Sajal K
authors.initials: SK
authors.lastname: Maity
authors.forename: Soumik
authors.initials: S
authors.lastname: Roy
authors.forename: Shuvendu
authors.initials: S
authors.lastname: Singha
authors.forename: Rina
authors.initials: R
authors.lastname: Ghosh
mesh_terms: D000080:Acetals / Q000737:chemistry; D001547:Benzaldehydes / Q000737:chemistry; D002240:Carbohydrate Sequence; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013865:Thioglycosides / Q000737:chemistry*
chemical_list: D000080:Acetals; D001547:Benzaldehydes; D002712:Chlorides; D005290:Ferric Compounds; D006027:Glycosides; D058116:Lewis Acids; D013865:Thioglycosides; C032175:benzaldehyde; C024555:ferric chloride; C059033:1,1-dimethoxyethane