Palladium-catalyzed coupling reactions: mechanism of reductive elimination. Progress report, October 1, 1980-June 30, 1981. [Ethane elimination from dimethylpalladium, propenylbenzene from styrylmethylpalladium]
The mechanisms of the reductive elimination of alkyl partners from palladium, particularly under reaction conditions characteristic of the palladium-catalyzed coupling of organic halides and organometals, can take place either from Pd(II) or Pd(IV). The coupling of alkyl groups from a dialkylpalladium(II) complex requires that the organic partners be cis to one another. The reaction is a first-order intramolecular process that sometimes requires prior dissociation of a ligand, leading to a Y-or T-shaped intermediate. Coupling also can take place by the prior oxidative addition of organohalide to the dialkylpalladium(II) complex to yield a palladium(IV) species from which reductive elimination takes place rapidly. The reductive elimination step takes place with retention of geometry at an sp/sup 2/ carbon, and retention of configuration at an sp/sup 3/ carbon. Which catalytic reversible cycle, Pd(O) ..-->.. Pd(II) or Pd(II) ..-->.. Pd(IV) operates depends on the organic groups, the ligands and the reaction solvent.
- Research Organization:
- Colorado State Univ., Fort Collins (USA)
- DOE Contract Number:
- AS02-78ER04903
- OSTI ID:
- 6293580
- Report Number(s):
- DOE/ER/04903-3; ON: DE81030169
- Country of Publication:
- United States
- Language:
- English
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Palladium catalyzed coupling reactions: mechanism of reductive elimination. Progress report, October 1, 1979-September 30, 1980. [Ethane elimination]
Related Subjects
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
AROMATICS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
COUPLING
ETHANE
HYDROCARBONS
KINETICS
LIGANDS
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PALLADIUM COMPLEXES
REACTION INTERMEDIATES
REACTION KINETICS
REDUCTION
RESEARCH PROGRAMS
TRANSITION ELEMENT COMPLEXES