The mechanism of highly stereospecific, Pd-catalyzed Stille cross-coupling of anomeric stannanes with aryl halides was investigated using density functional theory (DFT) calculations. The analysis of the computed activation barriers indicates that the reaction proceeds through a four-step process involving aryl halide oxidative addition, halide exchange to form an aryl palladium(II)fluoride, transmetallation, and C-C reductive elimination. The stereospecificity of the reaction is attributed to the preference for the stereoretentive cyclic transition state during the transmetallation. The configurational stability of the glycosyl-Pd(II) intermediates and the ligand effects to suppress undesired β-elimination pathways were also investigated using DFT calculations.

Computational study on the stereospecific cross-coupling reactions of anomeric stannanes for the synthesis of C-aryl glycosides

254th National Meeting (2017)

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