Dynamic features of the zirconocene-boron-betaine complexes obtained by treatment of bis(alkynyl)zirconocenes with the tris(pentafluorophenyl) borane Lewis-acid
作者:Wolfgang Ahlers、Bodo Temme、Gerhard Erker、Roland Fröhlich、Thomas Fox
DOI:10.1016/s0022-328x(96)06610-7
日期:1997.1
Bis(propynyl)zirconocene (6a) reacts with tris(pentafluorophenyl)borane to yield the carbon-carbon coupled Cp2M(μ-RC4R)B(C6F5)3 betaine product 4a (M Zr, R CH3). A variety of differently substituted analogs was prepared (M Zr, R = n-butyl, phenyl, cyclohexyl; M Ti, R CH3; M Hf; R CH3, phenyl, SiMe3). These complexes 4 are chiral due to the presence of a rather stable propeller-like RB(aryl)3
双(丙炔基)二茂锆(6A)反应与三(五氟苯基)硼烷,得到的碳-碳偶联的Cp 2 M(μ-RC 4 R)B(C 6 ˚F 5)3甜菜碱产品4A(M的Zr,R CH 3)。制备了各种不同取代的类似物(M 3 Zr,R =正丁基,苯基,环己基; M 3 Ti,R 3 CH 3; M 3 Hf; R 3 CH 3,苯基,SiMe 3)。由于存在相当稳定的螺旋桨状RB(芳基)3,这些配合物4是手性的构象。该系列配合物的许多例子的分子内对映体化过程的活化势垒是通过动态1 H NMR光谱法测定的,† G↕值范围约为。取决于取代模式,为13至16kcal mol -1。络合物4a与2,6-二甲基苯基异氰化物反应,得到通过X射线衍射表征的亚甲基环丙烯衍生物1。