Asymmetric carboncarbon bond forming reactions catalyzed by chiral Schiff base—titanium alkoxide complexes
作者:Masahiko Hayashi、Tetsuya Inoue、Yasunori Miyamoto、Nobuki Oguni
DOI:10.1016/s0040-4020(01)89374-1
日期:1994.4
The enantioselective addition of trimethylsilyl cyanide to a variety of aldehydes proceeded by the aid of a catalyst prepared in situ from titanium tetraisopropoxide [Ti(O-i-Pr)4] and chiral Schiff bases and gave the corresponding cyanohydrins in high optical yield (up to 96% e.e.). A remarkable rate enhancement was brought about by the addition of the Schiff base to the titanium alkoxide mediated
在由四异丙醇钛[Ti(O- i- Pr)4 ]和手性席夫碱原位制备的催化剂的帮助下,将三甲基甲硅烷基氰化物对映选择性加成到各种醛中,从而以高光学收率得到了相应的氰醇(最多到96%ee)。通过将席夫碱加入到钛醇盐介导的醛的甲硅烷基氰化中,可以显着提高速率。该催化剂体系还促进了双烯酮与醛的高度对映选择性反应,这导致形成光学活性的5-羟基-3-氧代酯。