title: A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides.
abstract: A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97%) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH⋅H2O (1 mol%) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
authors: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS (UK).
authors: Edward I
authors: EI
authors: Balmond
authors: David
authors: D
authors: Benito-Alifonso
authors: Diane M
authors: DM
authors: Coe
authors: Roger W
authors: RW
authors: Alder
authors: Eoghan M
authors: EM
authors: McGarrigle
authors: M Carmen
authors: MC
authors: Galan
mesh_terms: D002384:Catalysis; D006027:Glycosides / Q000737:chemistry*
chemical_list: D006027:Glycosides
keywords: conformation analysis; glycosides; homogeneous catalysis; protecting groups; synthetic methods