共查询到20条相似文献,搜索用时 500 毫秒
1.
手性螺环配体的合成及其在不对称催化反应中的应用研究进展 总被引:2,自引:0,他引:2
手性螺环配体的合成及其在不对称催化反应中的应用是不对称合成和催化研究中重要的研究领域之一, 一些手性螺环配体被合成出来并成功地应用于不对称催化反应中. 综述了近十年来手性螺环配体的合成及在不对称催化反应中的应用研究进展. 相似文献
2.
3.
4.
5.
手性金属配合物催化剂在不对称合成中占有重要地位[1-3]。在该类催化剂参与的不对称催化反应中,配合物中手性配体是催化反应立体选择性优劣的关键[4,5]。为了改进该类催化剂的性能,主要对手性配体进行过化学修饰。目前合成的手性催化剂几乎都是由同一种手性配体和一种金属离子组成的二元配合物,且高效者并不多.文献[6]曾提到有关手性三元配合物(亦称手性混合配体配合物)。在不对称催化中应用的可能性,但未见具体报道。本文以中性含氮配体和含氧酸与铜(Ⅱ)配位合成了一类手性三元铜(Ⅱ)配合物及其在不对称合成菊酸中的催化性能。 相似文献
6.
7.
8.
9.
10.
过渡金属参与的不对称催化反应是有机合成化学研究的前沿和热点. 寻找和发现新颖配体骨架并开展新型高效的手性配体及催化剂的设计合成是不对称催化反应研究的核心内容. 从20世纪90年代,特别是进入21世纪以来,螺环骨架手性配体受到了广泛的关注,并逐渐发展成为特色鲜明的手性配体类别. 手性螺环配体的骨架已由多手性的螺[4.4]壬烷骨架发展到只具有单一手性的螺二氢茚和螺[4.4]壬二烯等螺环骨架类型,形成了包括手性螺环单磷配体、双膦配体、膦氮配体、双氮配体等丰富的手性配体库. 这些手性螺环配体及其催化剂不仅在不对称催化氢化、不对称碳―碳键形成、不对称碳―杂原子键形成等多种类型的不对称催化反应中均表现出优异的催化活性和对映选择性,且使得许多原先难以控制对映选择性的不对称催化反应变得可能. 而今,手性螺环结构已成为“优势结构”,相应的手性螺环配体及其催化剂已被国内外同行广泛采用. 手性螺环配体的兴起为手性催化剂研究增加了活力,极大地促进了不对称合成化学的发展. 今后,手性螺环配体的研究除了将向新型、高效、高选择性手性配体及催化剂方向发展外,将其应用于新的不对称催化反应的对映选择性控制、以及应用于手性天然产物和药物的高效不对称合成将成为新的研究热点. 相似文献
11.
《Tetrahedron: Asymmetry》2006,17(4):642-657
A library of new fine-tunable monodentate phosphite and phosphoramidite ligands based on chiral biphenol have been designed and developed. These monodentate phosphorus ligands have exhibited excellent enantioselectivity in the Pd-catalyzed asymmetric allylic alkylation and Rh-catalyzed asymmetric hydrogenation. 相似文献
12.
A new and simple method for immobilization of monodentate chiral ligand on the cheap resin has been developed. A series of resin-immobilized phosphoramidite ligands based on BINOL and TADDOL backbones have been synthesized and characterized with gel-phase NMR. The immobilized ligands have been applied to the Pd-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate. Among four ligands, the supported bulky monodentate phosphoramidite ligand based on TADDOL backbone afforded the chiral product with ee up to 65%; moreover, this ligand could be recycled for 3 times without substantial decrease of the conversion and ee. 相似文献
13.
The design of new chiral ligands is the key in the development of transition metal catalyzed asymmetric synthesis. Many chiral diphosphine ligands have been prepared and applied in asymmetric catalytic reactions with excellent enantioselectivities. Among the chiral diphosphine ligands that have been reported, the atropisomeric C2-symmetric phosphines with a biaryl scaffold initiated by Noyori and co-workers with BINAP were found to have the widest application in the transition metal catalyze… 相似文献
14.
Xin Chang Pei‐Long Ma Hong‐Chao Chen Chuan‐Ying Li Peng Wang 《Angewandte Chemie (International ed. in English)》2020,59(23):8937-8940
Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh‐catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh‐catalyzed hydrogenation and a Pd‐catalyzed intramolecular carboamination. 相似文献
15.
Copper-catalyzed asymmetric conjugate addition of diethylzinc to nitroalkenes using new chiral monodentate phosphoramidite ligands proceeds with high enantioselectivity up to 99% ee. [reaction: see text] 相似文献
16.
17.
A palladium-catalyzed asymmetric allylation of isatins with allylic alcohols as an allyl donor was developed by using chiral spiro phosphoramidite ligands. A variety of chiral tertiary homoallylic alcohols 3-allyl-3-hydroxy-2-oxindoles were prepared directly from allylic alcohols in one step with excellent yields and moderate enantioselectivities. This represents the first catalytic asymmetric allylation of ketones with allylic alcohol as the allylating agent. 相似文献
18.
为了进一步拓展具有螺二氢茚骨架的亚磷酸酰胺酯、亚磷酸酯、亚膦酸酯等手性螺环单磷配体在不对称反应中的应用范围, 研究了手性螺环单磷配体在铑催化苯乙烯衍生物的氢甲酰化反应中的选择性. 相似文献
19.
Monti C Gennari C Piarulli U de Vries JG de Vries AH Lefort L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(22):6701-6717
A library of 19 chiral tropos phosphorus ligands, based on a flexible (tropos) biphenol unit and a chiral P-bound alcohol (11 phosphites) or secondary amine (8 phosphoramidites), was synthesized. These ligands were screened, individually and as a combination of two, in the rhodium-catalyzed asymmetric hydrogenation of dehydro-alpha-amino acids, dehydro-beta-amino acids, enamides and dimethyl itaconate. ee values up to 98% were obtained for the dehydro-alpha-amino acids, by using the best combination of ligands, a phosphite [4-P(O)2O] and a phosphoramidite [13-P(O)2N]. Kinetic studies of the reactions with the single ligands and with the combination of phosphite [4-P(O)2O] and phosphoramidite [13-P(O)2N] have shown that the phosphite, despite being less enantioselective, promotes the hydrogenation of methyl 2-acetamidoacrylate and methyl 2-acetamidocinnamate faster than the mixture of the same phosphite with the phosphoramidite, while the phosphoramidite alone is much less active. In this way, the reaction was optimized by lowering the phosphite/phosphoramidite ratio (the best ratio is 0.25 equiv phosphite/1.75 equiv phosphoramidite) with a resulting improvement of the product enantiomeric excess. A simple mathematical model for a better understanding of the variation of the enantiomeric excess with the phosphite/phosphoramidite ratio is also presented. 相似文献
20.
Peter N.M Botman Rieko van Heerbeek Henk Hiemstra Jan H van Maarseveen 《Tetrahedron letters》2004,45(31):5999-6002
The axially chiral BICOL backbone was functionalised with two third generation carbosilane dendritic wedges and further elaborated to a phosphoramidite ligand. High enantioselectivities were obtained when these monodentate ligands were applied in the rhodium-catalysed asymmetric hydrogenation of methyl 2-acetamidocinnamate. 相似文献