1,5-Cyclooctadiene palladium chloride complex

The palladium chloride complex of 1,5-cyclooctadiene is similarly prone to transannular bonding. A report by Chung and Scott described the smooth conversion of 46 to 47 at room temperature in the presence of lead tetraacetate.81 ... 

Sodium arylsulfinates and palladium salts react to form arylpaUadium salts and sulfur dioxide. When carried out in the presence of some dienes, stable organopalladium complexes have been obtained. For example, 1,5-cyclooctadiene and sodium p-toluenesulfinate with palladium chloride yields the a,it-complex shown in equation (48).109... 

Dien-4-ynes 136 (R -R = alkyl) are produced from propargylic carbonates 135 and terminal alkynes in the presence of a palladium-phosphine complex and copper(I) iodide. The linear co-dimerization of terminal acetylenes and 1,3-dienes is catalyzed by ruthenium(cyclooctadiene)(cyclooctatriene)(trialkylphosphine) (alkyl = Et, Bu or octyl) thus 1-hexyne and methyl penta-2,4-dienoate give a mixture of the eneynes 137 and 138. Coupling of octa-l,7-diyne (139) with the acetylenic bromo acid 140 in aqueous THF-methanol containing butylamine, hydroxylamine hydrochloride and copper(I) chloride gave a mixture of the triynyl acids 141 and 142. ... 

Similar studies have been reported for the complexes of norbornadiene with cuprous chloride (5) and palladium chloride 4). A complex of 1,3- and 1,4-cyclooctadiene with palladium chloride has been reported to be a useful catalyst for the polymerization of olefins (5). 

Palladium(II) complexes having olefin ligands such as 1,5-cyclooctadiene (COD), norbomene, or norbomadiene are not only readily available by reaction of palladium(II) chloride in the presence of the appropriate alkene, but also they are commercially available (Figure 5-3). In some cases, bispalladium(I) complexes can be isolated, too however, they are thermally unstable and decompose at ambient temperature. 

The complexes (l,5-cyclooctadiene)(2,4-pentanedionato)-palladium(II) and platinum(II) tetrafluoroborate are air-stable solids, soluble in polar organic solvents such as chloroform, methylene chloride, acetonitrile, acetone, or methanol but insoluble in nonpolar solvents such as alkanes, benzene, or ether. Their solutions in acetone have conductivities typical of 1 1 electrolytes. Their proton magnetic resonance spectra (in CDC13 solutions, internal tetramethylsilane reference at 60 MHz.) show peaks due to coordinated cyclooctadiene at 3.78 and 6.7-7.4r (Pd) and at 4.25 and 6.9-7.6r (Pt) and due to the chelated /3-diketone at 4.39 and 7.88r (Pd) and at 4.15 and 7.81r (Pt) with the expected area ratios. In the spectrum of the platinum compound coupling with the 95Pt isotope (33 %... 

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