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A Novel Highly Stereospecific Method of 1 ,2 - cis -glycosylation. Synthesis of α- D )- glucosyl - and α- D - galactosyl- D -hexoses
N. K. Kochetkov, E. M. Klimov, N. N. Malysheva, A. V. Demchenko
A. D. Zelinsky Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow
Abstract: A novel highly stereospecific method of 1,2-cis-glycoside linkage formation using glycosyl thiocyanates is developed. A new approach to protected β-hexosyl thiocyanates-is used starting from 1,2-cis-glycosyl halides and potassium thiocyanate in the presence of 18-crown-6. The thiocyanates are shown to be reactive, stereospecifically glycosylating agents in triphenylmethilium perchlorate-catalysed reaction with sugar trityl ethers. β-D-Glucopyranosyl and β-D-galactopyranosyl thiocyanates with a nonparticipating-group (OMe, OBn) at C-2 react stereospecifically with 2-, 3-, 4-, and 6-O-trityl-D-glucose-and 2-O-trityl-D-galactose derivatives and with a high yield α-linked disaccharides are-obtained.
Russian Journal of Bioorganic Chemistry 1990, 16 (5):701-710