Silver(I)-catalyzed addition of zirconocenes to glycal epoxides. A new synthesis of alpha-C-glycosides.

[reaction: see text] Hydrozirconation of terminal alkynes, followed by AgClO4-catalyzed in situ addition of the resultant alkenylzirconocenes to 1,2-anhydrosugars (glycal epoxides) leads to alpha-C-glycosides in moderate to high yields.