Reductive elimination of aryl carboxylates from acyl(aryloxy)nickel(II) and -palladium(II) complexes

Reductive Elimination of Anhydrides from Anionic Iodo Acetyl Carboxylato Rhodium Complexes

“…Komlya et al have studied reductive elimination reactions involving complexes of the type [(acyl)(aryloxy)M II L 2 ] (M = Ni or Pd) and observed that the presence of an aryloxy group bearing electron‐withdrawing groups and/or strong donor ligands in the coordination sphere of the metal centre brings enough stability to these complexes to allow their characterization before the reductive elimination produces RCOOR′ 9g. Various authors such as van Leeuwen,9a,9b Heaton9c and Cole‐Hamilton9h have studied the methanolysis of acyl–palladium(II) complexes, which is considered to be the last step of the methoxycarbonylation of alkenes, and proposed that this reaction proceeds by a metathesis‐type reaction or the coordination of methanol to the palladium centre prior to the intramolecular nucleophilic attack at the acyl carbon atom.…”

Chemistry of diamino-ligated methylpalladium(II) alkoxides and aryloxides (Part II): methoxide formation and carbonylation reactions

“…Subsequent reductive elimination of a carboxylic ester is possible from the insertion intermediate that results from either pathway. It is known that carbonylation of methylnickel(II) and methylpalladium(II) aryloxide complexes generates the corresponding acyl complexes by preferential migratory insertion of CO into the M-C bond rather than into the M-O bond, and acylnickel and acylpalladium complexes such as [M(COMe)(OC6H 4-CN-4)(PEt3) z] (M=Ni, Pd) have been successfully isolated from such reactions at low temperature [6]. Upon heating, the latter palladium(II) complex cleanly liberates the ester MeCOzC6HnCN-4.…”

“…Upon heating, the latter palladium(II) complex cleanly liberates the ester MeCOzC6HnCN-4. In the case of acylnickel(II) aryloxides, the reductive elimination of the ester must be assisted by addition of 7r-acids such as CO or olefins [6]. The corresponding methylnickel(II) and methylpalladium(II) alkoxides also react with carbon monoxide to afford the corresponding methyl esters [7]; however, the intermediates involved are different from those with aryloxide ligands.…”

Palladium‐Catalyzed Aminocarbonylation of Aryl Chlorides at Atmospheric Pressure: The Dual Role of Sodium Phenoxide

“…First, owing to its greater nucleophilicity compared to di‐ n ‐butylamine, NaOPh intercepts the palladium acyl species resulting from oxidative addition of the aryl chloride and migratory insertion of CO11 and leads to the formation of 13 12. 13 We suspect that this lower energy pathway, involving intermediate ester 13 , is the critical feature that allows lower operational temperatures in this method compared to previously reported systems that employ similar ligand/metal systems. Second, NaOPh acts as a Brønsted base in catalyzing the conversion of the intermediate phenyl ester to the amide product.…”