title: Stereochemistry in the synthesis and reaction of exo-glycals.
abstract: Two general methods are explored for the stereoselective synthesis of exo-glycals. One method utilizes a nucleophilic addition of fully protected sugar lactones of gluco-, galacto-, and manno-types, followed by the subsequent dehydration, to give the desired exo-glycals with (Z)-configuration. The other method proceeds with selenylation of C-glycosides in a stereoselective manner. The subsequent selenoxide elimination also provides (Z)-exo-glycals. The prepared exo-glycal conjugated esters of either gluco- or manno-type react with allyl alcohol to give exclusively alpha-anomers.
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, No. 128, Academia Road Section 2, Nan-Kang, Taipei 11529, Taiwan.
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Yang
authors.forename: Yu-Ying
authors.initials: YY
authors.lastname: Yang
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Gu
authors.forename: Shwu-Huey
authors.initials: SH
authors.lastname: Wang
authors.forename: Che-Chien
authors.initials: CC
authors.lastname: Chang
authors.forename: Chun-Hung
authors.initials: CH
authors.lastname: Lin
mesh_terms: D002236:Carbohydrate Conformation; D002241:Carbohydrates / Q000138:chemical synthesis*; D005690:Galactose / Q000737:chemistry; D007783:Lactones / Q000737:chemistry; D008358:Mannose / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D002241:Carbohydrates; D007783:Lactones; D008358:Mannose; D005690:Galactose