| Abstract
| - The inherent preference for the insertion and transmetalation routes is experimentally evaluated in the model reactions of appropriately substituted alkenylsilanes and palladium pentafluorophenyl complexes. The major pathway is insertion of the alkene and β-SiMe3 elimination, whereas transmetalation is a minor route in all cases.
- Reactions of alkenylsilanes (alkenyl = 2-propenyl, vinyl, allyl) with neutral and cationic palladiumaryl complexes [Pd(C6F5)X(NCMe)2] (X = Br, 1; Cl, 2), [Pd(C6F5)(acac)(NCMe)] (acac = acetylacetonate,3), and [Pd(C6F5)(bipy)(S)]ClO4 (S = acetone, 4) were studied. The compounds obtained were substitutedalkenylsilanes (formed via Heck substitution) and desilylated olefins (formed by transmetalation followedby reductive elimination or by insertion followed by β-SiMe3 elimination). The analysis of the structureof the final organic products provides a quantitative assessment of the importance of these competingpathways. Transmetalation to palladium was found to be a minor pathway in all cases, whereas insertionof the double bond into the Pd−C6F5 bond followed by β-SiMe3 elimination was the major route. Theformation of C6F5-substituted alkenylsilanes is favored when an excess of starting alkenylsilane is used.
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