Journal article
Mechanism of reductive elimination: Reaction of alkylpalladium(II) complexes with tetraorganotin, organolithium, and Grignard reagents. Evidence for palladium(IV) intermediacy
Journal of the American Chemical Society, Vol.101(17), pp.4981-4991
1979
Abstract
Coupling products are obtained in good yields from the reaction of tetraorganotin compounds or Grignard reagents and organohalogenopalladium(l 1) complexes provided that a benzyl bromide is present. Low yields are obtained in the absence of the benzyl bromides, in which case other decomposition pathways (e.g., a elimination) take place, even in the presence of electron acceptors (e.g., oxygen, /w-dinitrobenzene). The first step in the reaction of benzylhalogenobis(triphenylphosphine)-palladium(II) complexes with MeM (M = SnMe3, MgBr) is metathesis of the benzyl ligand rather than the halogen. This unique carbon-for-carbon transmetalation takes place at 25 °C and is facilitated by electron-donating substituents on the benzyl ligand. The products of this reaction subsequently react at higher temperature in the presence of a benzyl bromide to afford ethylbenzene. Optically active chloro-(a-deuteriobenzyl)bis(triphenylphosphine)palladium yields, upon reaction with tetramethyltin in the presence of p-nitrobenzyl bromide, optically active -deuterioethylbenzene in which overall retention of configuration at carbon has resulted. m-Dimethylbis(triphenylphosphine)palladium(!I) reacts with benzyl bromide at 25 °C to afford ethylbenzene and bromomethylbis(triphenylphosphine)palladium(ll) rather than ethane. When optically active a-deuteriobenzyl bromide is used in this reaction, optically active -deuterioethylbenzene is formed, and inversion of configuration at carbon takes place. The reductive elimination process is proposed to take place preferentially from a palladium(IV) intermediate with retention of configuration at carbon.
Details
- Title
- Mechanism of reductive elimination; Reaction of alkylpalladium(II) complexes with tetraorganotin, organolithium, and Grignard reagents. Evidence for palladium(IV) intermediacy
- Creators
- D. Milstein (null) - Colorado State UniversityJ. K. Stille (Corresponding Author) - Colorado State University
- Resource Type
- Journal article
- Publication Details
- Journal of the American Chemical Society, Vol.101(17), pp.4981-4991; 1979
- Number of pages
- 11
- Language
- English
- DOI
- https://doi.org/10.1021/ja00511a031
- Grant note
- This research was supported by the Department of Energy, Office of Basic Energy Sciences, Contract No. ER-78-S-02-4903.A000.
- Record Identifier
- 993267712003596
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