Stereoretentive elimination and trans-olefination of the dicationic dipalladium moiety [Pd2Ln]2+ bound on 1,3,5-trienes.
Stereoretentive elimination and trans-olefination of the dicationic dipalladium moiety [Pd2Ln]2+ bound on 1,3,5-trienes.
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结合在 1,3,5-三烯上的二价二钯部分 [Pd2Ln]2 的立体保留消除和反烯化。
DOI：
10.1021/ja0576740
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发表时间：
2006
影响因子：
15
通讯作者：
H. Kurosawa
中科院分区：
文献类型：
--
作者：
Tetsuro Murahashi;H. Nakashima*;Tomoki Nagai;Yukari Mino;Taketoshi Okuno;M. Jalil;H. Kurosawa
[Pd(2)(CH(3)CN)(6)][BF(4)](2)(1)与1,3,5-己三烯、1,6-二苯基-1,3,5-己三烯（DPHT）或2,2,9,9-四甲基-3,5,7-癸三烯（DBHT）反应得到双(3)-烯丙基二钯配合物3,4或5。在有氧条件下，在CD(2)Cl(2)中进行反应时，1与DBHT以立体定向（同步）方式进行反应，而在N(2)气氛下形成两种非对映体的混合物。分离了DBHT形成的2个非对映体（5-E，Z，E-antifacial和5-E，E,E-antifacial），并通过x射线衍射分析确定了1与（E，E，E）-DBHT反应形成的5-E，Z，E-antifacial的结构。将膦配体（PPh(3)或dppm）添加到乙腈中的双核加合物5-E，Z，E-antifacial或5-E，E，E-antifacial上，导致立体特异性（同步）消除[Pd(2)(PPh(3))(2)(CH(3)CN)(4)][BF(4)](2)(2)或[Pd(2)(dppm)(2)(CH(3)CN)(2)][BF(4)](2)(6)。在PPh(3)诱导的双核消除过程中，最初观察到磷化氢加合物7保留了双(3)-烯丙基双钯的结构。从5-E，E，E-antifacial中分离得到膦加合物，并通过x射线衍射分析对其结构进行了表征。1与DPHT在CH(2)Cl(2)中反应生成独特的双钯夹层化合物[Pd(2)(mu-eta(3):eta(3)-DPHT)(2)][BF(4)](2)(8)。夹层配合物和半夹层配合物之间的相互转化以立体保持的方式发生。通过x射线衍射分析确定了4-E、E、E-antifacial和（E，Z，E）-DPHT形成的夹层配合物8-E、Z、E的结构。双钯基团[Pd(2)(CH(3)CN)(4)]（2+）从4-E，E，E-antifacial的DPHT配体以立体保护的方式转移到DBHT配体上。所观察到的立体保持双核过程的特点是两个钯原子位于三烯π平面上的成对行为。在双核消除中，最初处于二价状态并在相反的面（反面）结合的两个Pd原子在解离之前到达合面位置形成Pd-Pd键。这些结果代表了共轭烯烃作为金属-金属多齿配体的独特性质。
The reaction of [Pd(2)(CH(3)CN)(6)][BF(4)](2) (1) with 1,3,5-hexatriene, 1,6-diphenyl-1,3,5-hexatriene (DPHT), or 2,2,9,9-tetramethyl-3,5,7-decatriene (DBHT) afforded bi-eta(3)-allyldipalladium complexes 3, 4, or 5. The reaction of 1 and DBHT proceeded in a stereospecific (syn) manner when the reaction was carried out in CD(2)Cl(2) under aerobic conditions, while a mixture of two diastereomers was formed under N(2) atmosphere. The two diastereomers (5-E,Z,E-antifacial and 5-E,E,E-antifacial) formed from DBHT were isolated, and the structure of 5-E,Z,E-antifacial, which was kinetically formed from the reaction of 1 and (E,E,E)-DBHT, was determined by X-ray diffraction analysis. Addition of phosphine ligands (PPh(3) or dppm) to the dinuclear adduct 5-E,Z,E-antifacial or 5-E,E,E-antifacial in acetonitrile resulted in the stereospecific (syn) elimination of [Pd(2)(PPh(3))(2)(CH(3)CN)(4)][BF(4)](2) (2) or [Pd(2)(dppm)(2)(CH(3)CN)(2)][BF(4)](2) (6). During the PPh(3)-induced dinuclear elimination, the phosphine adducts 7 that retain bi-eta(3)-allyldipalladium structure were observed initially. The phosphine adduct generated from 5-E,E,E-antifacial was isolated and structurally characterized by X-ray diffraction analysis. The reaction of 1 and DPHT in CH(2)Cl(2) afforded unique dipalladium sandwich compounds [Pd(2)(mu-eta(3):eta(3)-DPHT)(2)][BF(4)](2) (8). Interconversion between the sandwich complexes and half-sandwich complexes occurred in a stereoretentive manner. The structure of the sandwich complex 8-E,Z,E formed from 4-E,E,E-antifacial and (E,Z,E)-DPHT was determined by X-ray diffraction analysis. Transfer of the dipalladium moiety [Pd(2)(CH(3)CN)(4)](2+) from DPHT ligand of 4-E,E,E-antifacial onto DBHT ligand proceeded in a stereoretentive manner. The observed stereoretentive dinuclear process is featured by the pairwise behavior of two palladium atoms sitting on the triene pi-plane. In the dinuclear elimination, the two Pd atoms that are initially in the divalent state and bound on the opposite faces (antifacial) come to the synfacial positions to form a Pd-Pd bond prior to dissociation. These results represent the unique property of conjugated olefin as the multidentate ligands for metal-metal moieties.