A 2,3,5-tri-O-benzyl-D-ribose reacts with lithium salts of thiophenes
or furans to give the corresponding 2-ribosylthiophenes or furans, whi
ch are then treated with p-toluenesulfonic acid, affording 2-ribofuran
osylthiophenes or furans (C-nucleosides) in good yield and in a stereo
selective manner.