Synthesis of the C-glycosidic analogue 9 of adenophostin A, a very potent IP3 receptor agonist, and its uracil congener 10 was achieved via a temporary silicon-tethered radical coupling reaction as the key step. Phenyl 3,4,6-tri-O-(p-methoxybenzyl)-1-seleno-beta-D-glucopyranoside (27) and 3-deoxy3-methylene-1,2-O-isopropylidene-alpha-D-erythro (30) were connected by a dimethylsilyl tether to give the radical coupling reaction substrate 24, which was successively treated with Bu-3-SnH/AIBN in benzene and TBAF in THF to give the coupling product 25 with the desired (3a,1'a)-configuration as the major product. From 25, the targets 9 and 10 were synthesized via introduction of adenine or uracil base by Vorbruggen's method and phosphorylation of the hydroxyls by the phosphoramidite method.