Allylpalladium(II) Chloride Dimer

Chemical properties

Allylpalladium(II) chloride dimer is a yellow powder with the formula [(η3-C3H5)PdCl]2. This compound is an important catalyst used in organic synthesis. It is one of the most widely used transition metal allyl complexes.

The Uses of Allylpalladium(II) Chloride Dimer

Allylpalladium(II) chloride dimer is used as an important catalyst in Heck reaction. It reacts with cyclopentadienyl anion to give cyclopentadienyl allyl palladium. It acts as a precatalyst for asymmetric and cross-coupling catalysis. Further, it is used in the preparation of 1,4-diallyl-1,2-dihydroisoquinolines. It is also employed as a catalyst for greener Buchwald-Hartwig coupling reaction and involved in the synthesis of cationic palladium catalysts. In addition, it takes part in preparation of -heterocyclic carbene-palladium-eta3-allyl chloride complex, which is an efficient catalyst for the Suzuki-Miyaura cross-coupling reactions in synthetic chemistry.

The Uses of Allylpalladium(II) Chloride Dimer

[Pd(allyl)Cl]2 can be used as a catalyst:
For the silylation of organobromides.
To synthesize α-aryl carbonyl compounds by coupling reaction between aldehydes and aryl halides.
To prepare various arylthiophene derivatives by cross-coupling reaction with aryl halides via C-H functionalization.
Application Guide for Palladium Catalyzed Cross-Coupling Reactions
ChemDose: Convenient Dosing of Catalysts and Reagents

Preparation

Allylpalladium(II) chloride dimer is prepared by purging carbon monoxide through a methanolic aqueous solution of palladium(II) chloride, sodium chloride, and allyl chloride.
2Na2PdCl4 + 2 CH2=CHCH2Cl + 2 CO + 2 H2O → (C3H5)2Pd2Cl2 + 4 NaCl + 2 CO2 + 4 HCl

Reactions

1. Precatalyst for the enantioselective hydrosilylation of olefins.
2. Precatalyst for asymmetric allylic alkylation and amination.
3. Used as a palladium source for cross-coupling reactions.
4. Can be used with Trost ligands.
5. Catalyst for the carbostannylation of alkynes.
6. Used as a precatalyst for "-arylation of aldehydes.

General Description

Allylpalladium(II) chloride dimer is employed as catalyst in Heck reaction. It also participates as catalyst in the tandem nucleophilic allylation-alkoxyallylation reaction of the alkynylaldehydes with allyl chloride and allyltributylstannane.

Purification Methods

It crystallises from benzene and is soluble in MeOH, Et2O and CHCl3. [Hüttel et al. Chem Ber 94 766 1961, Dent et al. J Chem Soc 1585 1964, Armstrong J Org Chem 31 618 1966.]