Stereochemistry in palladium- and nickel-catalyzed addition of phenylmagnesium bromide to unsaturated carbohydrates

Abstract Palladium complex PdCl 2 (dppf) and nickel complex NiCl 2 (dppe) catalyze cross-coupling of unsaturated aryloxy carbohydrates with phenylmagnesium bromide. The nickel catalyst leads to inversion of configuration at the anomeric center while only retention occurs in the case of the palladium catalyst. This quite unusal retention is probably due to the influence of the ring oxygen atom