114656-33-6

Upstream product

• 98933-74-5 tri-n-butyl-(3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl)stannane 
• 114656-28-9 2-methyl-1-(3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexapyranosyl)-1-propanol 
• 91780-35-7 3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl chloride 
• 78-84-2 isobutyraldehyde 

Relevant academic research and scientific papers

SmI2-promoted chemistry at the anomeric center of carbohydrates. Reductive formation and reaction of glycosyl samarium (III) reagents

Reaction of 3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyl chloride at room temperature with the efficient single electron transfer system of SmI2-THF-HMPA, in the presence of cyclopentanone (Barbier conditions) gave selectively the corresponding α-C-glycoside in 70percent yield.It is postulated that the reactive transient intermediate is a chiral anomeric organosamarium (III) species.Lower yields were obtained in the presence of aldehydes, such as n-butanal or isobutanal.It is also demonstrated that glycosyl phenyl sulfones undergo reductive samariation. 2,3,4,6-Tetra-O-benzyl-β-D-glucopyranosyl phenyl sulfone reacted with cyclopentanone, in the presence of SmI2-THF-HMPA, to give the corresponding β-C-glycoside selectively in 25percent yield, together with the elimination product (40percent).When the protecting group at C-2 was an acetate, a very fast β-elimination of the organosamarium intermediate occurred to give a practically quantitative yield of a substituted glycal.This work constitutes the first application of samarium(II) iodide to the reductive metallation of the anomeric center of carbohydrates.Key words: samarium diiodide / sulfones / carbohydrates / glycals / C-glycosides

STEREOCONTROLLED PREPARATION OF C-2-DEOXY-α- AND -β-D-GLUCOPYRANOSYL COMPOUNDS FROM TRIBUTYL-(2-DEOXY-α- AND -β-D-GLUCOPYRANOSYL)STANNANES

Tributylstannyllithium treatment of 3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyl chloride (2) provided selectively tributyl (3,4,6-tri-O-benzyl-2-deoxy-β-D-arabino-hexopyranosyl)stannane (3) in 85percent yield.Isomeric tributyl (3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyl)stannane (6) could be prepared in 70percent yield by reductive lithiation of 2 and reaction with tributyltin chloride.Tin-lithium exchange reaction, performed on 3 and 6 with butyllithium in oxolane at -78 deg C, generated the corresponding, configurationally stable 2-deoxy-β- and -α-D-hexopyranosyllithium compounds which reacted with electrophilic compounds with retention of configuration.Addition of these glycosyllithium reagnts to prochiral carbonyl compounds gave variable degrees of facial selectivity.A significant diastereofacial discrimination (10:1) was observed by condensation of 3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyllithium reagent with hexanal and isobutyraldehyde.The structure of all C-glycopyranosyl compounds obtained was established by 1H-n.m.r. spectroscopy.