Gold(I)-catalyzed rearrangement of glycosyl ortho-allenylbenzoates leading to the formation of C-glycosides

A gold(I)-catalyzed rearrangement of glycosyl ortho-allenylbenzoates leading to the formation of C-glycosides has been disclosed. The reaction proceeds via fragmentation of the glycosyl ortho-allenylbenzoate into glycosyl cation and 3-[phosphine gold(I)methyl]-1H-isochrmen-1-one intermediates and their subsequent recombination, with the later allyl gold(I) intermediate being successfully trapped and characterized.