473545-22-1Relevant academic research and scientific papers
Convergent and convenient total synthesis of phytoalexin-elicitor active heptasaccharide by one-pot sequential glycosylation
Mukaiyama, Teruaki,Ikegai, Kazuhiro,Hashihayata, Takashi,Kiyota, Koichi,Jona, Hideki
, p. 730 - 731 (2002)
Convergent and convenient total synthesis of branched hepta-β-glucoside 1 having phytoalexin-elicitor activity was efficiently accomplished by way of two one-pot sequential glycosylation reactions. Trisaccharide 8 was synthesized in high yield by TfOH-catalyzed one-pot glycosylation using three component monosaccharides and subsequent selective deprotection of a 6′-O-TBDPS group. The second one-pot glycosylation of trisaccharide 8 with the three monosaccharides smoothly proceeded to afford heptaglucoside 11 stereoselectively in 48% total yield based on monosaccharide 3. The targeted compound 1 was obtained in high yield after the removal of the protecting groups.
Convergent total syntheses of oligosaccharides by one-pot sequential stereoselective glycosylations
Hashihayata, Takashi,Ikegai, Kazuhiro,Takeuchi, Kazuya,Jona, Hideki,Mukaiyama, Teruaki
, p. 1829 - 1848 (2007/10/03)
A convergent total synthesis of F1α antigen, a member of the tumor-associated O-linked mucin glycosyl amino acid, was tried by one-pot sequential glycosylation. Highly α-selective glycosylation of amino acid 7 with thioglycoside 6 was successfully carried out by combining trityl trifluoromethanesulfonate (TrOTf) and N-iodosuccimide (NIS) which gave glycosyl amino acid 21 in high yield (97%, α/β = 83/17). Next, the glycosylation of thioglycoside 4 with galactosyl phenyl carbonate 2 or fluoride 3 was tried by the promotion of trityl tetrakis(pentafluorophenyl)borate [TrB(C6F5)4] or trifluoromethanesulfonic acid (TfOH); protected F1α 25 was afforded in 80 or 89% overall yield, respectively, by the further addition of glycosyl amino acid 5 and NIS. The desired trisaccharide was obtained in high yield after removal of the protecting groups. Next, a convergent total synthesis of branched hepta-β-glucoside 30 having phytoalexin-elicitor activity was efficiently performed by way of two one-pot sequential glycosylation reactions: that is, trisaccharide 34 was synthesized in high yield by TfOH-catalyzed one-pot glycosylation using three given monosaccharides (31, 35, and 36) as shown in Scheme 12 and by subsequent selective deprotection of 6′-O-TBDPS group. The second one-pot glycosylation of trisaccharide 34 with three monosaccharides (31, 32, and 33d) also proceeded smoothly to afford heptaglucoside 43 stereoselectively in 48% total yield based on monosaccharide 32. Phytoalexin-elicitor active branched hepta-β-glucoside 30 was afforded by the sequential deprotection.
