146933-97-3Relevant academic research and scientific papers
SmI2-promoted chemistry at the anomeric center of carbohydrates. Reductive formation and reaction of glycosyl samarium (III) reagents
Pouilly, P. de,Chenede, A.,Mallet, J.-M.,Sinay, P.
, p. 256 - 265 (2007/10/02)
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
