centers through the sulfur and alkene donor functions. These complexes catalyze the conjugate addition of arylboronic acids to cyclic Michael acceptors with enantioselectivities of up to 99% ee. DFT calculations show the preponderant influence of planar chirality of the ligand alkene function. The enantioselectivity switch observed between (RS,SC)-11 and (RS,RC)-12 is explained by the inverted cis–trans
苯基二苯并[去质子化B,F ] tropylidene(8)用
LDA /吨-BuOK基
葡萄糖接着用廉价的非对映体任一淬火吨-Bu-亚
磺酸盐([R或( - )小号) - 11次,得到亚砜烯烃混合(S S ,S C)-9 /(S S ,R C)-10和(R S ,R C)-9 /(R S ,S C)-10的非对映体对分别通过色谱/重结晶可将其分离成四个异构体。光学纯的非对映体
配体(S S ,S C)-9和(S S ,R C)-10与[RhCl(coe)2 ] 2反应形成双核络合物(R S ,S C)-11和(R S ,R C)-12,其中双齿
配体通过
硫和烯烃供体的功能配位
金属中心。这些络合物以高达99%ee的对映选择性催化芳基
硼酸与环状Michael受体的共轭加成。DFT计算显示了
配体烯烃官能团的平面手性的主要影响。在(R S ,S C)-11和(R S ,R C)-12之间观察到的对映选择性