[en] Reaction of 3,4,6-tri-ο-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 70% 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-ο-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 25% yield, together with the elimination product (40%). 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