Associative Transmetalation in the Stille Cross-Coupling Reaction to Form Dienes: Theoretical Insights into the Open Pathway
Citations Over TimeTop 14% of 2008 papers
Abstract
The open transmetalation mechanism for the Stille cross-coupling of vinylbromide and vinyl triflate with trimethylvinylstannane catalyzed by Pd(PMe3)2 as well as the roles of a coordinating solvent molecule (DMF) and additive (LiCl) have been theoretically studied using density functional theory (DFT). The cyclic mechanism seems to be favored for vinyl bromides. In contrast, the open alternative is likely followed by triflates. An oxidative addition mechanism involving a rearrangement of the triflate group on the Pd(PMe3)2(η2-vinyl triflate) complex has been characterized. The open transmetalation pathway for vinyl triflate involves the more electrophilic palladium species generated by the substitution of the triflate by a ligand Y (PMe3, DMF) on the oxidative addition intermediate. Moreover, LiCl as additive is shown to favor the oxidative addition step of triflates by forming an anionic trivalent species, [Pd(PMe3)2Cl]−. The square-planar trans-[Pd(PMe3)2(vinyl)Cl] complex generated by reaction with vinyl triflate corresponds formally to the product of direct oxidative addition of vinyl chloride to Pd(PMe3)2, which then would follow the cyclic transmetalation pathway.
Related Papers
- → A Critical Analysis of the Cyclic and Open Alternatives of the Transmetalation Step in the Stille Cross-Coupling Reaction(2006)109 cited
- → Effect of the Leaving Ligand X on Transmetalation of Organostannanes (vinylSnR3) with LnPd(Ar)(X) in Stille Cross-Coupling Reactions. A Density Functional Theory Study(2006)68 cited
- → Observation of a Hidden Intermediate in the Stille Reaction. Study of the Reversal of the Transmetalation Step(2008)44 cited
- → ”Copper Effect” in Migita–Kosugi–Stille Coupling Revisited(2021)
- → ”Copper Effect” in Migita–Kosugi–Stille Coupling Revisited(2021)