Halides, aryl complexes

Palladium complexes also catalyze the carbonylation of halides. Aryl (see 13-13), vinylic, benzylic, and allylic halides (especially iodides) can be converted to carboxylic esters with CO, an alcohol or alkoxide, and a palladium complex. Similar reactivity was reported with vinyl triflates. Use of an amine instead of the alcohol or alkoxide leads to an amide. Reaction with an amine, AJBN, CO, and a tetraalkyltin catalyst also leads to an amide. Similar reaction with an alcohol, under Xe irradiation, leads to the ester. Benzylic and allylic halides were converted to carboxylic acids electrocatalytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions. ... 

Aryl chlorothioformates, 23 628 Aryl complexes, zirconium, 26 655 Aryl ethers, uses for, 70 581 2-Arylglycine esters, 72 166 Aryl halide amination, 9 278 Aryl halides, reaction with carbon monoxide, 5 11 Arylhydrazines, 9 270 Arylmethane dyes, 9 503... 

The cis/trans isomerization of platinum(II) complexes is a subject which will be discussed in some detail when the halide (Group VII) complexes are covered. Nevertheless the importance of reductive elimination reactions of platinum(II) alkyl and aryl complexes makes it imperative that this reaction be discussed here for alkyl and aryl platinum(II) compounds. 

The most common route to alkyl or aryl complexes of the type [AuRL] is by the treatment of a halide complex with an alkyl- or aryllithium reagent. The first reactions of this type were performed (15) in 1959 [Eq. (5)], and the methyl and phenyl compounds were found to have chemical and thermal stabilities intermediate between those of the previously known organopalladium and -platinum complexes. 

Alkyl and aryl complexes of the type [AuRL] may also be prepared by reaction of a halide complex with a Grignard reagent. Thus have been... 

When the nickel complexes [NiX2(PPh3)2] (X = Cl, Br) are reduced electrochemically in the presence of C02 and aryl halides, aryl carboxylate anions are formed.585 The reduction leads to nickel(O) complexes which then undergo oxidative addition of the aryl halide followed by insertion of C02. Further reduction then gives the product and regenerates nickel(O) (Scheme 55). 

The products of oxidative addition of acyl chlorides and alkyl halides to various tertiary phosphine complexes of rhodium(I) and iridium(I) are discussed. Features of interest include (1) an equilibrium between a five-coordinate acetylrhodium(III) cation and its six-coordinate methyl(carbonyl) isomer which is established at an intermediate rate on the NMR time scale at room temperature, and (2) a solvent-dependent secondary- to normal-alkyl-group isomerization in octahedral al-kyliridium(III) complexes. The chemistry of monomeric, tertiary phosphine-stabilized hydroxoplatinum(II) complexes is reviewed, with emphasis on their conversion into hydrido -alkyl or -aryl complexes. Evidence for an electronic cis-PtP bond-weakening influence is presented. 

An alternative pathway when soluble alkoxide or silylamido bases are used, involves reaction of a palladium amido aryl complex with the alkoxide or silylamide to form an intermediate alkoxide or amide. These complexes can react with amines to form the required amido aryl intermediate. This pathway seems to occur for aryl halide animations catalyzed by complexes with chelating ligands. The inorganic... 

Closely related are the -acyl complexes of iron (115). These have been prepared by three methods. Loss of N2 from (112) in the presence of an alkyl halide gives oxidative addition see Oxidative Addition) to yield ) -acyl complexes for some phosphine ligands. Sodium amalgam reduction of Fe halide complexes (116), and exposme of the resulting (117) to an alkyl halide, gives similar complexes (equation 24). Finally, placement of iron alkyl (aryl) complexes (118) under a CO atmosphere results in insertion to afford complexes (119) (equation 25). ... 

A number of other chiral ligands are available, but have been studied much less extensively. Hie chiral diamines (106) and (107) are reported to mediate the reactions between aryl Grignards and aldehydes (Bgure 22 equation 26). Hie alcohols range in optical purity from 40 to 75% ee selectivities increase with the bulkiness of the aldehyde substituent (see Table 28). Hie use of an aiyloxy metal halide to complex the aldehyde moiety enhances the observed enantioselectivities. °... 

Oxidative addition of a Sn-H bond, which produces a species containing a M-Sn bond, was considered earlier (10.3.8.3). Platinum complexes, in particular, also react by oxidative addition of bonds between Sn and halide, aryl, alkyl, or Sn to produce species containing Pt-Sn bonds. 

Palladium-catalyzed cross couplings of organofluorosilanes with vinyl [37] and aryl [38] halides and triflates are known, where the activation of the Si—C bond by fluoride ion plays an essential role in the coupling. The pentacoordinated fluoroorganic silanes promote the transmetallation to the aryl halide-palladium complexes strongly. At least one fluorine... 

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