Lithiation-based silylation and stannylation of 6-chloro-9-(beta-D-ribofuranosyl)purine.

Reaction of the lithiated species of 9-(2,3,5-tris-O-tert-butyldimethylsilyl-beta-D-ribofuranosyl)-6-chloropu rine with Me3SiCl or Bu3SnCl was found to furnish the corresponding C-2 substituted product, as a result of silyl or stannyl migration from C-8 to C-2 position.