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Catalytic and stoichiometric reactions of Arylpalladium(II) complexes bearing a trans-chelating dinitrogen ligand with arylboronic acids
Journal of Organometallic Chemistry ( IF 2.3 ) Pub Date : 2019-12-23 , DOI: 10.1016/j.jorganchem.2019.121088
Yuji Suzaki , Takashi Saito , Kohtaro Osakada

Pd(II) complexes with 1,2-bis(2′-pyridylethylnyl)benzene (bpeb) ligand, PdCl2(bpep) and Pd(OAc)2(bpep), catalyze cross-coupling of arylboronic acids and aryl iodide, in spite of the trans-chelation of the ligand. Arylpalladium iodo and trifluoroacetate complexes with bpep ligand, Pd(C6H4X-4)(I)(bpep) (3a-3h, X = OMe, Me, H, COMe, CHO, COOEt, NO2, F), Pd(C6H3F2-2,4)(I)(bpep) (3i), Pd(C6H4X-4)(OCOCF3)(bpep) (4a-4e, X = OMe, Me, H, COMe, CHO) and Pd(C6F5)(OCOCF3)(bpep) (4j), were obtained by ligand exchange of the Pd complexes having tmeda ligand (tmeda = N,N,N′,N′-tetramethylethylenedi-amine). X-ray crystallographic results of arylpalladium(II) trifluoroacetate complex, Pd(C6H4OMe-4)(OCOCF3)(bpeb) (4a), and bis(trifluoroacetate)palladium(II) complex, Pd(OCOCF3)2(bpeb) (5) revealed the structures with two pyridyl groups of bpeb coordinated to Pd(II) in a trans-chelating bidentate mode. 2-Pyridyl hydrogens and an acetate oxygen of 5 are at close positions to each other (2.52 and 2.66 Å). The reaction of (4-MeC6H4)B(OH)2 (7b) with Pd(C6H4OMe-4)(OCOCF3)(bpeb) (4a) in the presence of Ag2O yields Pd(C6H4Me-4)(OCOCF3)(bpeb) (4b) via exchange of the aryl group between the palladium complex and arylboronic acid. The reaction of (4-CHOC6H4)B(OH)2 (7e) yields not only Pd(C6H4CHO-4)(OCOCF3)(bpeb) (4e) but also biaryls, 4-MeOC6H4-C6H4Y-4 (Y = OMe (8a), CHO (8e)). Hammett plots of the reaction exchange suggest higher reactivity of the Pd complex with more electron-donating aryl ligand.



中文翻译:

带有反式螯合二氮配体的芳基钯(II)配合物与芳基硼酸的催化和化学计量反应

具有1,2-双(2'-吡啶基乙炔基)苯(bpeb)配体,PdCl 2(bpep)和Pd(OAc)2(bpep)的Pd(II)络合物催化芳基硼酸和芳基碘的交叉偶联尽管配体反式螯合。具有bpep配体Pd(C 6 H 4 X-4)(I)(bpep)的芳基碘钯和三氟乙酸盐络合物(3a-3h,X = OMe,Me,H,COMe,CHO,COOEt,NO 2,F), Pd(C 6 H 3 F 2 -2,4)(I)(bpep)(3i),Pd(C 6 H 4 X-4)(OCOCF 3)(bpep)(4a-4e,X = OMe,Me ,H,COMe,CHO)和Pd(C通过具有tmeda配体(tmeda =NNN ′,N′-四甲基乙二胺)的Pd络合物的配体交换获得了 6 F 5)(OCOCF 3)(bpep)(4j)。芳基钯(II)三氟乙酸盐络合物Pd(C 6 H 4 OMe-4)(OCOCF 3)(bpeb)(4a)和双(三氟乙酸盐)钯(II)络合物Pd(OCOCF 3)的X射线晶体学结果2(bpeb)(5)揭示了具有两个bpeb吡啶基的结构与Pd(II)配位的反式结构。-螯合双齿模式。2-吡啶基氢和乙酸氧为5彼此靠近(2.52和2.66Å)。在Ag 2 O存在下(4-MeC 6 H 4)B(OH)27b)与Pd(C 6 H 4 OMe-4)(OCOCF 3)(bpeb)(4a)的反应生成Pd( C 6 H 4 Me-4)(OCOCF 3)(bpeb)(4b)通过在钯配合物和芳基硼​​酸之间交换芳基进行。(4-CHOC 6 H 4)B(OH)27e的反应)不仅会生成Pd(C 6 H 4 CHO-4)(OCOCF 3)(bpeb)(4e),还会生成联芳基4-MeOC 6 H 4 -C 6 H 4 Y-4(Y = OMe(8a), CHO(8e))。反应交换的哈米特图表明,Pd配合物具有更多的供电子芳基配体,具有更高的反应性。

更新日期:2019-12-23
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