稀土金属在不对称催化中的应用:从均相催化到异相催化

稀土金属的配位数较高,可通过容纳大型手性配体,构筑手性环境,催化不对称反应的定向发生,在工业生产特别是制药工程中具有重要应用价值.本文以Henry反应、Mannich反应和Strecker反应为例,总结回顾了稀土金属催化剂在此类反应中的设计思路、性能特点与应用前景,旨在展现稀土金属催化剂兼具融合均相催化与异相催化的优势...     

Cyclopentadienyl-Free Organolanthanide Chemistry

During the past ten years the organometallic chemistry of the lanthanides has witnessed enormous growth. One of the main reasons for this development was the finding that lanthanide metallocenes can exhibit an unusually high catalytic activity. Considerable advances have also been achieved in the chemistry of organolanthanide complexes that are not stabilized by cyclopentadienyl ligands. For example, the successful synthesis of the first unsolvated homoleptic trialkyllanthanides, [Ln{CH(SiMe₃)₂}₃], has recently been reported. Anionic allyl complexes of the lanthanides show promising catalytic properties and cyclooctatetraene complexes of these elements are also under active investigation. This review is intended to provide an overview of this rapidly developing area of research.     

手性金属Salen配合物在不对称催化中的应用*

手性Salen金属配合物已在不对称催化中得到了广泛的应用。本文主要介绍了可溶性的手性金属Salen配合物在不对称催化反应中的应用以及手性金属Salen配合物固载化研究取得的进展。     

Phosphoramidites: Privileged Ligands in Asymmetric Catalysis

Asymmetric catalysis with transition‐metal complexes is the basis for a vast array of stereoselective transformations and has changed the face of modern synthetic chemistry. Key to this success has been the design of chiral ligands to control the regio‐, diastereo‐, and enantioselectivity. Phosphoramidites have emerged as a highly versatile and readily accessible class of chiral ligands. Their modular structure enables the formation of ligand libraries and easy fine‐tuning for a specific catalytic reaction. Phosphoramidites frequently show exceptional levels of stereocontrol, and their monodentate nature is essential in combinatorial catalysis, where a ligand‐mixture approach is used. In this Review, recent developments in asymmetric catalysis with phosphoramidites used as ligands are discussed, with a focus on the formation of carbon–carbon and carbon–heteroatom bonds.     

官能团化的手性联芳基单齿膦配体在不对称均相金催化反应中的应用

自2005年以来, 不对称均相金催化反应研究取得了显著的进展, 并在有机合成中得到了广泛应用. 近年来, 官能团化的联芳基单齿膦配体在金催化反应中显露头角, 为不对称金催化反应提供了新的发展思路. 本文综合评述了这一领域的研究进展, 着重介绍了近年来利用这类配体实现的金催化不对称反应及反应过程中配体与底物间相互作用.     

Asymmetric Phase-Transfer Catalysis

Both in the laboratory and industrially , phase-transfer catalysis offers the potential to induce asymmetry into reactions with anionic intermediates. Equation (a) provides an example (conditions: a) 10 mol % phase-transfer catalyst, BnBr, CsOH⋅H₂O, PhMe, 15–24 h, −78°C).     

Recent Advances in the Development of Chiral Gold Complexes for Catalytic Asymmetric Catalysis

Asymmetric gold catalysis has been rapidly developed in the past ten years. Breakthroughs have been made by rational design and meticulous selection of chiral ligands. This review summarizes newly developed gold-catalyzed enantioselective organic transformations and recent progress in ligand design (since 2016), organized according to different types of chiral ligands, including bisphosphine ligands, monophosphine ligands, phosphite-derived ligands, and N-heterocyclic carbene ligands for asymmetric gold(I) catalysis as well as heterocyclic carbene ligands and oxazoline ligands for asymmetric gold(III) catalysis.     

杂双金属复合物ZABDP催化芳香酮与芳香醛的直接不对称Aldol反应

合成了新型的手性铝/锌杂双金属复合物(R,S,S)-3,3'-二[(N-二苯基脯氨醇)甲基]-2,2'-二羟基-1,1'-联萘酚铝/锌复合物(ZABDP).在催化芳香酮与芳香醛的羟醛缩合(Aldol)反应中,该复合物中的铝作为路易斯酸活化醛,锌的烷氧化物作为Br?nsted碱,使苯乙酮形成活性锌的烯醇化物,2种金属的应用使得芳香醛与芳香酮的直接不对称Aldol反应顺利进行,反应的对映选择性最高达90%,产率最高达99%.     

Schiff base过渡金属配合物在不对称催化中的应用

综述了Ｓｃｈｉｆｆｂａｓｅ过渡金属配合物在不对称催化烯烃环氧化、氮杂环丙烷化、环丙烷化和其它催化反应中的应用研究进展，参考文献３９篇。     

Comparing Neutral (Monometallic) and Anionic (Bimetallic) Aluminum Complexes in Hydroboration Catalysis: Influences of Lithium Cooperation and Ligand Set

Bimetallic lithium aluminates and neutral aluminum counterparts are compared as catalysts in hydroboration reactions with aldehydes, ketones, imines and alkynes. Possessing Li–Al cooperativity, ate catalysts are found to be generally superior. Catalytic activity is also influenced by the ligand set, alkyl and/or amido. Devoid of an Al?H bond, iBu₂Al(TMP) operates as a masked hydride reducing benzophenone through a β‐Η transfer process. This catalyst library therefore provides an entry point into the future design of Al catalysts targeting substrate specific transformations.     

Asymmetric Catalysis Mediated by the Ligand Sphere of Octahedral Chiral‐at‐Metal Complexes

Due to the relationship between structure and function in chemistry, access to novel chemical structures ultimately drives the discovery of novel chemical function. In this light, the formidable utility of the octahedral geometry of six‐coordinate metal complexes is founded in its stereochemical complexity combined with the ability to access chemical space that might be unavailable for purely organic compounds. In this Minireview we wish to draw attention to inert octahedral chiral‐at‐metal complexes as an emerging class of metal‐templated asymmetric “organocatalysts” which exploit the globular, rigid nature and stereochemical options of octahedral compounds and promise to provide new opportunities in the field of catalysis.     

Progress towards Bioorthogonal Catalysis with Organometallic Compounds

The catalysis of bioorthogonal transformations inside living organisms is a formidable challenge—yet bears great potential for future applications in chemical biology and medicinal chemistry. We herein disclose highly active organometallic ruthenium complexes for bioorthogonal catalysis under biologically relevant conditions and inside living cells. The catalysts uncage allyl carbamate protected amines with unprecedented high turnover numbers of up to 270 cycles in the presence of water, air, and millimolar concentrations of thiols. By live‐cell imaging of HeLa cells and with the aid of a caged fluorescent probe we could reveal a rapid development of intense fluorescence within the cellular cytoplasm and therefore support the proposed bioorthogonality of the catalysts. In addition, to illustrate the manifold applications of bioorthogonal catalysis, we developed a method for catalytic in‐cell activation of a caged anticancer drug, which efficiently induced apoptosis in HeLa cells.     

Synergistic Ir/Cu Catalysis for Asymmetric Allylic Alkylation of Oxindoles: Enantio- and Diastereoselective Construction of Quaternary and Tertiary Stereocenters

3,3-Disubstituted oxindoles bearing quaternary and tertiary stereogenic centers are privileged structural motifs, which widely exist in pharmaceutical and natural products. Herein, a highly regio-, enantio-, and diastereoselective allylic alkylation of 3-alkyl oxindoles through synergistic iridium and copper catalysis is described, which provides a series of 3,3-disubstituted oxindole derivatives containing adjacent quaternary and tertiary stereogenic centers in excellent yields, enantiomeric excess, and diastereomeric ratio (for 30 examples, up to 97 % yield, >99 % ee, and >20 : 1 dr). This method provides exclusive branched selectivity, excellent enantio- and diastereoselectivities, and good functional compatibility. Control experiments suggested that the chiral copper catalyst is required for achieving high reactivities and diastereoselectivities under mild reaction conditions.     

Towards Perfect Asymmetric Catalysis: Additives and Cocatalysts

Make your catalyst more enantioselective! The enantiomeric excess of a catalytic reaction system can sometimes be enhanced from below 10 to over 90 % by the use of suitable achiral additives. Since completely different mechanisms can influence the catalyst and reaction outcome, there is a range of additives that can be applied to improve the catalyst efficiency for a variety of organic reactions.     

Asymmetric Electrochemical Catalysis

Asymmetric electrochemical catalysis, an emerging frontline in asymmetric catalysis and electro-organic synthesis, is summarized. Representative works are classified, with respect to the external chiral resources, including chiral media, chiral mediator, chiral catalyst, and chiral electrode. This concept article is expected to provide readers with the general concepts and perspectives of each chiral electrochemical catalysis mode, and to indicate the potential and future development of asymmetric electrochemical catalysis.     

Asymmetric Catalysis with Chiral Frustrated Lewis Pairs

The chemistry of frustrated Lewis pairs (FLPs) provides the most important approach for the metal‐free hydrogenation and hydrosilylations. Great progress has been achieved in this area for the past decade. Some promising results have also been obtained. This perspective article mainly focuses on the recent advances for the synthesis of chiral Lewis acidic boranes in category of three protocols, 1) hydroboration of chiral internal alkenes with Piers’ borane HB(C₆F₅)₂; 2) in situ hydroboration of chiral alkenes or alkynes without any purification; 3) and substitution reaction of (C₆F₅)_nBCl_3–n with chiral organometallic reagents, as well as their applications in the metal‐free asymmetric hydrogenations and hydrosilylations.