Palladium-Catalyzed One-Step Synthesis of Stereodefined Difunctionalized Glycals

Efficiently modifying glycals by directly introducing functional groups into their double bonds is a longtwo different functional groups into 1-iodoglycals to obtain modified glycals in one step through palladium catalysis was reported for the first time, and the modified glycals contained stereodefined tetrasubstituted olefins. Using this method, various difunctionalized glycals that were difficult to form by other routes were synthesized in moderate to good yields. Control experiments and density functional theory calculations show that the palladium catalyst played dual roles in this transformation, namely, inducing nucleophilic substitution and catalyzing Suzuki coupling. The reaction intermediate was isolated and confirmed by X-ray crystallographic analysis. Furthermore, the gram-scale synthesis and facile deprotection of the target compound enhances the practicality of this strategy. [GRAPHICS] .