Hydrosilylation of dienes by yttrium hydrido complexes containing a linked amido-cyclopentadienyl ligand
作者:Alexander A. Trifonov、Thomas P. Spaniol、Jun Okuda
DOI:10.1039/b406071g
日期:——
The dimeric hydrido complex [Y(L)(THF)(μ-H)]2
(2) containing the CH2SiMe2-linked amido-cyclopentadienyl ligand L = C5Me4CH2SiMe2NCMe32− catalyzed the hydrosilylation of 1,5-hexadiene, 1,7-octadiene and vinylcyclohexene by PhSiH3. As demonstrated for 1,7-octadiene, the product distribution of the hydrosilylation strongly depends on the molar ratio of the reagents. In the absence of PhSiH3, the stoichiometric reaction of 2 with 1,5-hexadiene gave the isolable crystalline cyclopentylmethyl complex [Y(L)CH2CH(CH2)4}(THF)]
(3). Internal olefins such as trans-stilbene and alkynes such as tert-butylacetylene were not hydrosilylated by 2. trans-Stilbene was inserted into the yttrium–hydride bond of 2 to give the 1,2-diphenylethyl complex [Y(L)CH(CH2Ph)Ph}(THF)]
(4). tert-Butylacetylene reacted with 2 to give the dimeric acetylide [Y(L)(CCCMe3)]2
(5). In an attempt to detect the monomeric hydrido species as a DME adduct [Y(L)H(DME)], complex 2 was reacted with DME to form the sparingly soluble, dimeric 2-methoxyethoxy complex [Y(L)(μ-OCH2CH2OMe-κO)]2
(6) under C–O splitting.
二聚氢化物配合物 [Y(L)(THF)(μ-H)]₂ (2),其中 L = C₅Me₄CH₂SiMe₂NCMe₃²⁻,催化了 1,5-己二烯、1,7-辛二烯和乙烯环己烯与 PhSiH₃ 的氢硅化反应。如对 1,7-辛二烯所示,氢硅化的产物分布强烈依赖于试剂的摩尔比。在没有 PhSiH₃ 的情况下,复合物 2 与 1,5-己二烯进行化学计量反应,给出了可分离的结晶环戊基甲基配合物 [Y(L)CH₂CH(CH₂)₄}(THF)] (3)。如顺式苯乙烯和叔丁炔等内部烯烃未被 2 氢硅化。顺式苯乙烯插入到 2 的钇-氢键中,生成了 1,2-二苯乙基配合物 [Y(L)CH(CH₂Ph)Ph}(THF)] (4)。叔丁炔与 2 反应生成二聚炔类 [Y(L)(CCCMe₃)]₂ (5)。为了探测作为 DME 加合物的单体氢化物物种 [Y(L)H(DME)],复合物 2 与 DME 反应,形成了难溶性二聚 2-美氧乙氧基配合物 [Y(L)(μ-OCH₂CH₂OMe-κO)]₂ (6),伴随 C–O 键断裂。