Abstract
In this study, the addition of boranes to (E)-(η5-C5H5)2Zr(CH=CHPh)Cl (3) has been examined in order to investigate the regioselectivity of these ‘hydroboration’ reactions. We have found that these additions proceed with remarkable selectivity to give exclusive formation of a saturated organic molecule where one carbon atom has both the boron and the zirconium fragments. These reactions do not proceed via a conventional hydroboration reaction, but instead go through an initial transmetalation step to generate (E)-(η5-C5H5)2Zr(H)Cl (1) and the corresponding alkenyl boron intermediate, whereupon subsequent hydrozirconation of this latter species gives the geminal products. An x-ray diffraction study has been conducted on gem-(η5-C5H5)2Zr(CH(Bpin)CH2Ph)Cl (pin = 1, 2-O2C2Me4) (2). Crystals of 2 were orthorhombic with a = 18.545(3) Å, b = 15.713(3) Å, c = 16.157(3) Å in the space group Pccn. An x-ray diffraction study has also been conducted on the trinuclear zirconium oxide species (η5-C5H5)2ZrO2[ZrCl(η5-C5H5)2]2(4). Crystals of 4 were orthorhombic with a = 13.6000(8) Å, b = 14.2252(8) Å, c = 17.6500(10) Å in the space group P2(1)2(1)2(1).
在这项研究中,已经研究了将
硼烷添加到(E)-(η5-
C5H5)2Zr(CH=CHPh)Cl(3)中,以探究这些“氢
硼化”反应的区域选择性。我们发现这些加成反应以显著的选择性进行,仅形成一个饱和有机分子,其中一个碳原子同时具有
硼和
锆片段。这些反应不是通过传统的氢
硼化反应进行的,而是通过一个初始的
金属转移步骤生成(E)-(η5- )2Zr(H)Cl(1)和相应的烯基
硼中间体,随后对后者的氢
锆化产生了双官能团产物。对gem-(η5- )2Zr(CH(Bpin)CH2Ph)Cl(pin = 1, 2-O2C2Me4)(2)进行了X射线衍射研究。2的晶体为正交晶系,空间群为Pccn,a = 18.545(3) Å,b = 15.713(3) Å,c = 16.157(3) Å。还对三核
锆氧化物(η5- )2ZrO2[ZrCl(η5- )2]2(4)进行了X射线衍射研究。4的晶体为正交晶系,空间群为P2(1)2(1)2(1),a = 13.6000(8) Å,b = 14.2252(8) Å,c = 17.6500(10) Å。