97390-35-7Relevant academic research and scientific papers
Lifetime of the glucosyl oxocarbenium ion and stereoselectivity in the glycosidation of phenols with 1,2-anhydro-3,4,6-tri-O-methyl-α-D-glucopyranose
Chiappe, Cinzia,Lo Moro, Giacomo,Munforte, Paola
, p. 10471 - 10478 (1997)
The glycosidation of para substitued phenols with 1,2-anhydro-3,4,6-tri-O-methyl-α-D-glucopyranose. ZnCl2 catalyzed, gives predominatly the corresponding α-anomers. In the presence of an amino base, 1,1,3,3-tetramethylguanidine, however, enhances the β-selectivity, which becomes practically complete when tile reaction is carried out under basic conditions, by addition of K2CO3 and 18-crown-6. A rationaliation based on the lifetime of the oxocarbenium ion intermediate and on the nucleophilicity of the phenols is proposed.
