An efficient synthesis of 7-functionalized 7-deazapurine beta-D- Or beta-L-ribonucleosides: glycosylation of pyrrolo[2,3-D]pyrimidines with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-Or L-ribofuranose.

The glycosylation reaction performed with 7-halogenated 7-deazapurines employing commercially available 1-O-acetyl-2,3,5-tri-O-benzoyl-D- or L-ribofuranoses is described.