Stereochemistry in the synthesis and reaction of exo-glycals.
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.
Yang
Wen-Bin
WB
Institute of Biological Chemistry, Academia Sinica, No. 128, Academia Road Section 2, Nan-Kang, Taipei 11529, Taiwan.
Yang
Yu-Ying
YY
Gu
Yu-Feng
YF
Wang
Shwu-Huey
SH
Chang
Che-Chien
CC
Lin
Chun-Hung
CH
D002236:Carbohydrate Conformation; D002241:Carbohydrates / Q000138:chemical synthesis*; D005690:Galactose / Q000737:chemistry; D007783:Lactones / Q000737:chemistry; D008358:Mannose / Q000737:chemistry; D013237:Stereoisomerism
D002241:Carbohydrates; D007783:Lactones; D008358:Mannose; D005690:Galactose