手性联萘酚树状分子在不对称环氧化反应中的应用

Application of chiral BINOL bearing-dendrimer in asymmetric epoxidation reaction

研究将合成的新型可重复使用的含手性联萘酚的C3对称树状分子配体(L)与二乙基锌螯合制成了1个手性自负载的催化剂(L/Zn)。为研究该催化剂在查尔酮衍生物不对称环氧化反应中的手性诱导作用,将该催化剂用于(E)-α,β-不饱和芳基酮的不对称环氧化反应中,进行了反应条件的优化和底物拓展,并进一步探索了回收后的催化剂在以上不对称反应中的催化效率。结果表明,该催化剂应用于以上不对称环氧化反应中,对映体产物最好能达到99%的产率,对映体过量值最高可达76%,该自负载催化剂(L/Zn)仅经过简单的过滤洗涤过程就能够从反应混合物中回收,重复使用4次,其催化活性和对映选择性有所降低。

A new type of reusable C3-symmetrical BINOL dendrite ligand(L)was chelated with diethyl zinc to give a self-loading chiral catalyst(L/Zn).In order to study the chiral induction effect,the asymmetric epoxidation of chalcone derivatives was catalyzed by the chiral catalyst.C3-symmetrical BINOL ligand was applied in asymmetric epoxidation reaction of(E)-α,β-unsaturated aromatic ketone,the reaction condition was optimized and the substrate was extended.Further,the recycled catalyst was used more than once to explore induction effect of reclaimed ligand.The results indicate that the yield of enantiomers can reach as high as 99% when the catalyst is applied in above asymmetric epoxidation reaction,and enantiomeric excess can reach as high as 76%.The self-loading chiral catalyst(L/Zn)can be recovered from the mixture after simple filtration and washing process.The catalytic activity and enantioselectivity of catalyst have lowered after four times reuse.