Reactivity of ortho-β-Enaminone-phenyl Palladium Complexes. Insertion of CO into the Pd−C Bond to Give the First Acyl C,N,O-Pincer Complexes. Sequential Insertion of Dimethylacetylen

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• 作者：Jos Vicente ; Mara Teresa Chicote ; Antonio Jess Martnez-Martnez ; Antonio Abelln-Lpez ; Delia Bautista
• 刊名：Organometallics
• 出版年：2010
• 出版时间：November 8, 2010
• 年：2010
• 卷：29
• 期：21
• 页码：5693-5707
• 全文大小：1267K
• 年卷期：v.29,no.21(November 8, 2010)
• ISSN：1520-6041

文摘

Insertion of CO into the Pd−C_aryl bond of complexes [PdI{C₆H₄{NHC(Me)CHC(O)Me}-2}(NN)] afforded the benzoyl derivatives [PdI{C(O)C₆H₄{NHC(Me)CHC(O)Me}-2}(NN)] [NN = 4,4′-di-tert-butyl-2,2′-dipyridyl (^tBubpy) (1a), N,N,N′,N′-tetramethylethylenediamine (tmeda) (1b)]. The reactions of [Pd{C,C-C₆H₄{NH═C(Me)CHC(O)Me}-2}(tmeda)]OTf (OTf = CF₃SO₃) with excess CO and tmeda (2:1) or HOTf (1:1) produced the dinuclear benzoyl complex [{Pd{C,N,O-{C(O)C₆H₄{NC(Me)CHC(O)Me}-2}₂(μ-tmeda)] (2) or [Pd₂{μ-O,C,N,O′-{O═CC₆H₄{NC(Me)CHC(O)Me}-2}₂}] (3), respectively. The latter reacted with anionic or neutral ligands to give complexes Bu₄N[{Pd{C,N,O-{C(O)C₆H₄{NC(Me)CHC(O)Me}-2}₂(μ-OH)] (4), Q[Pd{C,N,O-{C(O)C₆H₄{NC(Me)CHC(O)Me}-2}}Cl] [Q = PPN (5a), NMe₄ (5b)], or [{Pd{C,N,O-{C(O)C₆H₄{NC(Me)CHC(O)Me}-2}L] (L = CN^tBu (6a), CNXy (6b), PPh₃ (6c), NH₃ (6d), NH₂Me (6e), MeCN (6f), dmso (6g)), respectively. The reaction of dimethylacetylenedicarboxylate (DMAD) with [PdI{C₆H₄{NHC(Me)CHC(O)Me}-2}(tmeda)] (1:1) afforded [PdI{C₆H₄{NHC(Me)C{Z-C(CO₂Me)═CH(CO₂Me)}C(O)Me}}-2}(tmeda)] (7Z), resulting from the insertion of the alkyne into the C(sp²)−H bond of the enaminone substituent. 7Z isomerized into the E analogue (7E) when heated in toluene at 95 °C and reacted in two steps with AgClO₄ and XyNC (1:1:2) to give the C,N,O-pincer derivative Pd{C,N,O-{C(═NXy)C₆H₄{NC(Me)C{C(CO₂Me)═CHCO₂Me)}C(O)Me}-2}(CNXy)] (8) as a mixture of the Z and E isomers. The latter complex converted, after a photochemical oxygenation, into the palladacycle [Pd{C,N,O-{C(═NXy)C₆H₄{N(dmoc)}-2](CNXy)]·2CHCl₃ (9), where the imino substituent dmoc is the cycle 1,2-di(methoxycarbonyl)-3-oxocyclopent-1-ene-4-yl. Compound 8 or 9 reacted with triflic or picric acid to give the species Pd{C,N,O-{C(═NHXy)C₆H₄{NC(Me)C{C(CO₂Me)═CHCO₂Me)}C(O)Me}-2}(CNXy)]OTf (10) or [Pd{C,N,O-{C(═NXy)C₆H₄{N(dmoc)}-2](CNXy)]·Hpic (11; Hpic = picric acid), respectively. The crystal structures of complexes 2, 3, 5a, 6b, 6c, 6e, 7Z, 7E, and 10 have been determined.