Treatment of 1-alkoxy-3-phospholene 1-oxide with lithium diisopropylamide followed by novel stereoselective C-alkylation with alkyl halides afforded 2-alkyl- and 2-benzyloxymethyl-3-phospholene 1-oxides, which were subjected to osmium (VIII) oxide-catalyzed diastereoselective cis-dihydroxylation to give new C-glycoside derivatives of furanose-type phosphono sugars, with twist conformation.