Reaction kinetics and mechanism of acid-catalyzed anomerization of 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose.
The mechanism of the acid-catalyzed anomerization of 1-O-acetyl-2,3,5-O-benzoyl-alpha- and -beta-L-ribofuranoses in different acetic acid-acetic anhydride mixtures was investigated. The progress of the reactions was followed by NMR spectroscopy and the rate constants for the reactions were determined by the use of a kinetic model. The site of anomeric activation was clarified by the use of (13)C-labeled acetic acid and acetic anhydride, respectively, proving that the anomerization takes place by exocyclic C-O cleavage, thus ruling out anomerization via acyclic intermediates. The role of the acetyl cation as the catalytically active species was further verified.
Forsman
Jonas J
JJ
Laboratory of Organic Chemistry, Abo Akademi University, Abo, Finland.
Wärnå
Johan
J
Murzin
Dmitry Yu
DY
Leino
Reko
R
D000085:Acetates / Q000737:chemistry; D000089:Acetic Anhydrides / Q000737:chemistry; D000107:Acetylation; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009005:Monosaccharides / Q000737:chemistry*; D013237:Stereoisomerism; D013464:Sulfuric Acids / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
C511842:1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose; D000085:Acetates; D000089:Acetic Anhydrides; D002712:Chlorides; D009005:Monosaccharides; D013464:Sulfuric Acids; D017967:Zinc Compounds; C031800:acetic anhydride; C016837:zinc chloride