Synergistic enhancement of catalytic activity of InCl3-Me3SiCl combination towards carbon Ferrier Rearrangement in glycal derivatives

InCl3 ( 2 mol%) in combination with Me3SiCl ( 20 mol%) efficiently catalyze Ferrier rearrangement in a variety of glycal derivatives with different silyl nucleophiles to afford the corresponding C-pseudoglycals or unsaturated pyrans in nearly quantitative yields. The stereoselectivity of the C-glycosides are good to excellent in favour of the alpha- anomers. A stoichiometric amount of InCl3 is necessary for similar transformations in the absence of Me3SiCl. The InCl3 can be recovered and reused without any loss of its activity.