| Abstract
| - 3,7-Anhydro-d-glycero-d-ido-octitol 1,5,6-trisphosphate (5) was designed as a novel IP3-receptorligand having a C-glycosidic structure and was synthesized via a radical cyclization reaction witha temporary connecting vinylsilyl tether as the key step. The phenyl 2-O-dimethylvinylsilyl-3,4,6-tri-O-benzyl-1-seleno-β-d-glucopyranoside (7), in the usual 4C1-conformation, was successivelytreated with Bu3SnH/AIBN and under Tamao oxidation conditions to give a mixture of fiveC-glycosidic products. On the other hand, similar successive treatment of the corresponding 3,4-di-O-TBS-protected substrates 13 and 24, which were in an unusual 1C4-conformaion due to thesteric repulsion between the bulky silyl protecting groups, gave the desired 1α-C-glycosides 18and 25, respectively, as the major products. Thus, the course of the radical cyclization was effectivelycontrolled by a change in the conformation of the pyranose ring into a 1C4-form due to steric repulsionbetween the adjacent bulky TBS-protecting groups at the 3- and 4-hydroxyl groups. From 25, thetarget 5 was synthesized via phosphorylation of the hydroxyls by the phosphoramidite method.The C-glycoside trisphosphate 5 has significant binding affinity for IP3 receptor of calf cerebella.
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