Synthesis of chiral salalen ligands and their in-situ generated Cu-complexes for asymmetric Henry reaction
作者:Ashish Dixit、Pramod Kumar、Surendra Singh
DOI:10.1002/chir.23019
日期:2018.12
Chiral salalen ligands derivedfrom (S)‐proline and derivatives of salicyaldehydes were synthesized, and their in‐situ generated Cu (II) complexes were evaluated in the asymmetric Henry reaction. Salalen ligand of different substituents on the phenyl moiety showed remarkable effect on the enantioselectivity of nitro‐aldol product of 4‐nitrobenzaldehyde and nitromethane. Cu (II) complex generated in
合成了衍生自(S)-脯氨酸和水杨醛衍生物的手性Salalen配体,并在不对称Henry反应中评估了它们原位生成的Cu(II)配合物。苯基部分上不同取代基的Salalen配体对4-硝基苯甲醛和硝基甲烷的硝基羟醛产物的对映选择性表现出显着影响。与(S)-2-(叔丁基)-6(((2-((((2-羟基-3-甲基苄基)氨基)甲基)吡咯烷烃-1-基)甲基)生成的Cu(II)络合物苯酚(10 mol%)和Cu(OAc)2 .H 2O(10 mol%)被发现是4-硝基苯甲醛与硝基甲烷之间硝基-羟醛反应的较好催化剂,40小时后,在35°C下,异丙醇中的相应产物收率为85%,对映体过量(ee)为88%。还以不同的取代的苯甲醛用于亨利反应的催化剂和相应的产物以22%至99%的产率和66%至92%的ee获得。4-硝基苯甲醛与前手性硝基乙烷的亨利反应产生抗选择性产物(dr = 79/21; anti / syn),收率为91%,ee为80%。
Synthesis of salicylaldehydes bearing bulky substituents in the positions 3 and 5
作者:A. I. Kochnev、I. I. Oleynik、I. V. Oleynik、S. S. Ivanchev、G. A. Tolstikov
DOI:10.1007/s11172-007-0170-5
日期:2007.6
4-disubstituted phenols with paraformaldehyde in the presence of SnCl4 and 2,6-lutidine afforded a number of new salicylaldehydes, containing bulky substituents (tert-butyl, 1-phenylethyl, 1-(4-tert-butylphenyl)ethyl, α-cumyl, and trityl) in the positions 3 and 5.
A group of modified (salen)Cr(III)Cl complexes with bulky benzylic substituents in the 3,3′-position of the salicylidene moiety have been successfully applied for the asymmetric nitroaldolreaction. The readily accessible complex bearing 3-phenylpent-3-yl groups (2 mol %) leads to β-nitro alcohols in up to 92% yield and 94% ee.
Design of postmetallocene catalytic systems of arylimine type for olefin polymerization: XVI. Synthesis of (N-aryl)salicylaldimines containing pent-4-enyloxy group and their complexes with titanium(IV) dichloride
作者:I. I. Oleinik、I. V. Oleinik、D. E. Zaitsev、S. S. Ivanchev、G. A. Tolstikov
DOI:10.1134/s1070428014020092
日期:2014.2
Reactions of p-(pent-4-enyloxy)aniline with salicylaldehyde containing versatile substituents in the positions 3 and 5 in an open system without solvent at 130°C afforded a series of (N-aryl)salicylaldimines, which with TiCl2(OPr-i)2 formed complexes of titanium(IV) dichloride L2TiCl2.
Structure/Properties Relationship for Bis(phenoxyamine)Zr(IV)-Based Olefin Polymerization Catalysts: A Simple DFT Model To Predict Catalytic Activity
作者:Gianluca Ciancaleoni、Natascia Fraldi、Roberta Cipullo、Vincenzo Busico、Alceo Macchioni、Peter H. M. Budzelaar
DOI:10.1021/ma300343c
日期:2012.5.22
The productivity of a number of bis(phenoxyamine)Zr(IV)-based catalysts (bis(phenoxyamine) = N,N′-bis(3-R1-5-R2-2-O-C6H2CH2)-N,N′-(R3)2-(NCH2CH2N)) in ethene and propene polymerization was evaluated for different R1/R2/R3 combinations. In previous studies on this class we demonstrated that the cations that form upon precatalyst activation (e.g., by methylalumoxane) adopt a “dormant” mer-mer geometry
多种基于双(苯氧基胺)Zr(IV)的催化剂的生产率(双(苯氧基胺)= N,N'-双(3-R 1 -5-R 2 -2-OC 6 H 2 CH 2)-对于不同的R 1 / R 2 / R 3组合,评估了乙烯和丙烯聚合中的N,N '-(R 3)2-(NCH 2 CH 2 N))。在对这一类的以前的研究,我们证明了阳离子即在前段催化剂活化(例如,由甲基铝氧烷)的形式采取“休眠”滨海聚体的几何形状,和吸热异构化到活动fac-fac几何形状是催化循环的必要第一步。因此,我们报告了催化剂活性与DFT计算的活性态和休眠态之间的能量差ΔE i之间的明显相关性。只有在对离子对进行计算时,相关性才成立,这并不像可能出现的那样明显,因为这些系统中的阴离子不在催化剂前沿。该发现提供了相对简单且快速的方法来预测相同类别的新催化剂的活性。