132884-86-7Relevant articles and documents
Synthesis and Properties of (η3-1-Methylallyl)palladium(II) Formates as Models of Intermediates in the Palladium-Catalyzed Reductive Cleavage of Allylic Carboxylates and Carbonates with Formic Acid
Oshima, Masato,Sakamoto, Toshiaki,Maruyama, Yooichiroh,Ozawa, Fumiyuki,Shimizu, Isao,Yamamoto, Akio
, p. 453 - 464 (2007/10/03)
In order to gain insight into the mechanism of the regioselective formation of alkenes in the palladium-catalyzed reductive cleavage of allylic carboxylates or carbonates with formic acid, two types of (η3-1-methylallyl)palladium formates (P1 and P2 types) have been prepared as simple models of catalytic intermediates. The P1 type is a neutral complex coordinated with one tertiary phosphine ligand and a formato ligand: [Pd(η3-MeCHCHCH2)(O2CH)(L)] (L = PMePh2, PMe2Ph, PMe3, P(o-tolyl)3); the P2 type is a cationic complex bearing two tertiary phosphine ligands and a formate counter anion: [Pd(η3-MeCHCHCH2)L2]+CO2H- (L = PMePh2, PMe2Ph, PMe3). The structures and dynamic behavior of the complexes in solution have been examined in detail by NMR spectroscopy. Studies on the thermolysis of the P1 and P2-type complexes have clearly provided the following mechanistic viewpoints: (1) 1-butene and 2-butene are formed from the P1 species; (2) butadiene is liberated from the P2 species; (3) the ratio of 1-butene to 2-butene increases as the bulkiness of phosphine ligand increases. A mechanism involving two geometrical isomers of [Pd(η3-MeCHCHCH2)(H)(L)], which are formed by decarboxylation of the P1-type complexes, has been proposed for the formation of butenes.
Synthesis and properties of (π-allyl)palladium formates as intermediates in palladium-catalyzed reductive cleavage of allylic acetates and carbonates with formic acid
Oshima, Masato,Shimizu, Isao,Yamamoto, Akio,Ozawa, Fumiyuki
, p. 1221 - 1223 (2008/10/08)
Neutral (π-allyl)(tertiary phosphine)palladium formates and ionic (π-allyl)bis(tertiary phosphine)palladium formates that are regarded as key intermediates in palladium-catalyzed reductive cleavage of allylic acetates and carbonates with formic acid have been prepared and characterized by 1H and 13C NMR spectroscopy. From a study of the formation process of these formate intermediates by anion exchange of the acetate anion with formic acid and by establishment of the course of liberation of olefins and CO2 from the formate ligand, the validity of the proposed catalytic cycle has been substantiated.
