The reaction of organolithium, Grignard, and organoaluminum reagents with 2'- and 3'-ketouridine derivatives was examined. For the reaction of 2', 5'-bis-0- (tert-butyldimethylsilyl) -3'-ketouridine, both organolithiums and organoaluminums seem to be practically useful. But only organoaluminums gave satisfactory yields in the reaction of 3', 5'-0- (tetraisopropyldisiloxan-1, 3-diyl) -2'-ketouridine.