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1.
Michael Dieckmann Yun‐Suk Jang Nicolai Cramer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(41):12317-12320
The cyclopentadienyl (Cp) group is a very important ligand for many transition‐metal complexes which have been applied in catalysis. The availability of chiral cyclopentadienyl ligands (Cpx) lags behind other ligand classes, thus hampering the investigation of enantioselective processes. We report a library of chiral CpxIrIII complexes equipped with an atropchiral Cp scaffold. A robust complexation procedure reliably provides CpxIrIII complexes with tunable counterions. In a proof‐of‐concept application, the iodide‐bearing members are shown to be highly selective for enyne cycloisomerization reactions. The dehydropiperidine‐fused cyclopropane products are formed in good yields and enantioselectivities. 相似文献
2.
Access to P‐ and Axially Chiral Biaryl Phosphine Oxides by Enantioselective CpxIrIII‐Catalyzed C−H Arylations 下载免费PDF全文
Yun‐Suk Jang Dr. Łukasz Woźniak Dr. Julia Pedroni Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2018,57(39):12901-12905
An enantioselective C?H arylation of phosphine oxides with o‐quinone diazides catalyzed by an iridium(III) complex bearing an atropchiral cyclopentadienyl (Cpx) ligand and phthaloyl tert‐leucine as co‐catalyst is reported. The method allows access to a) P‐chiral biaryl phosphine oxides, b) atropo‐enantioselective construction of sterically demanding biaryl backbones, and also c) selective assembly of axial and P‐chiral compounds in excellent yields and diastereo‐ and enantioselectivities. Enantiospecific reductions provide monodentate chiral phosphorus(III) compounds having structures and biaryl backbones with proven importance as ligands in asymmetric catalysis. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(47):15284-15288
An enantioselective C−H amidation of phosphine oxides by using an iridium(III) catalyst bearing an atropchiral cyclopentadienyl (Cpx) ligand is reported. A very strong cooperative effect between the chiral Cpx ligand and a phthaloyl tert‐leucine enabled the transformation. Matched–mismatched cases of the different acid enantiomers are shown. The amidated P‐chiral arylphosphine oxides are formed in yields of up to 95 % and with excellent enantioselectivities of up to 99:1 er. Enantiospecific reduction provides access to valuable P‐chiral phosphorus(III) compounds. 相似文献
4.
Dr. Tatsuhiko Yoshino Shun Satake Prof. Dr. Shigeki Matsunaga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(33):7346-7357
Transition-metal-catalyzed C−H functionalization reactions with Cp*MIII catalysts (M=Co, Rh, Ir) have found a wide variety of applications in organic synthesis. Albeit the intrinsic difficulties in achieving catalytic stereocontrol using these catalysts due to their lack of additional coordination sites for external chiral ligands and the conformational flexibility of the Cp ligand, catalytic enantioselective C−H functionalization reactions using the Group 9 metal triad with Cp-type ligands have been intensively studied since 2012. In this minireview, the progress in these reactions according to the type of the chiral catalyst used are summarized and discussed. The development of chiral Cpx ligands the metal complexes thereof, artificial metalloenzymes, chiral carboxylate-assisted enantioselective C−H activations, enantioselective alkylations assisted by chiral carboxylic acids or chiral sulfonates, and chiral transient directing groups are discussed. 相似文献
5.
Houhua Li Rajesh Gontla Jana Flegel Christian Merten Slava Ziegler Andrey P. Antonchick Herbert Waldmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):313-317
Herein, we report the first enantioselective annulation of α‐arylidene pyrazolones through a formal C(sp3)?H activation under mild conditions enabled by highly variable RhIII‐Cpx catalysts. The method has a wide substrate scope and proceeds with good to excellent yields and enantioselectivities. Its synthetic utility was demonstrated by the late‐stage functionalization of drugs and natural products as well as the preparation of enantioenriched [3]dendralenes. Preliminary biological investigations also identified the spiropyrazolones as a novel class of Hedgehog pathway inhibitors. 相似文献
6.
Shou‐Guo Wang Nicolai Cramer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2536-2540
A chiral CpxRhIII catalyst system in situ generated from a CpxRhI(cod) precatalyst and bis(o‐toluoyl) peroxide as activating oxidant was developed for a C?H activation/ring‐opening sequence between aryl ketoxime ethers and 2,3‐diazabicyclo[2.2.1]hept‐5‐enes. This transformation provides access to densely functionalized chiral cyclopentenylamines in excellent yields and enantioselectivities of up to 97:3 er. The reported method is also well suitable for asymmetric alkenyl C?H functionalizations of α,β‐unsaturated oxime ethers, furnishing skipped dienes with high levels of enantiocontrol. 相似文献
7.
Xifa Yang Guangfan Zheng Xingwei Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):328-332
Chiral rhodium(III) cyclopentadienyl catalysts (CpXRhIII) play significant roles in asymmetric arene C?H activation. Rh/Ir‐catalyzed couplings of arenes and strained rings have been well‐studied, but they have been limited to racemic systems. Reported in this work is the CpxRhIII/AgSbF6‐catalyzed enantioselective desymmetrizative C?C coupling of N‐pyrimidylindoles and 7‐azabenzonorbornadienes with high efficiency and enantioselectivity. The role of AgSbF6 has been established by mechanistic studies. AgSbF6 enhances the catalytic activity by suppressing the C3?H activation of the indoles, activation which would otherwise lead to catalytically inactive species. 相似文献
8.
Chiral Carboxylic Acid Enabled Achiral Rhodium(III)‐Catalyzed Enantioselective C−H Functionalization 下载免费PDF全文
Dr. Luqing Lin Seiya Fukagawa Daichi Sekine Eiki Tomita Dr. Tatsuhiko Yoshino Prof. Dr. Shigeki Matsunaga 《Angewandte Chemie (International ed. in English)》2018,57(37):12048-12052
Reported is an achiral CpxRhIII/chiral carboxylic acid catalyzed asymmetric C?H alkylation of diarylmethanamines with a diazomalonate, followed by cyclization and decarboxylation to afford 1,4‐dihydroisoquinolin‐3(2H)‐one. Secondary alkylamines as well as nonprotected primary alkylamines underwent the transformation with high enantioselectivities (up to 98.5:1.5 e.r.) by using a newly developed chiral carboxylic acid as the sole source of chirality to achieve enantioselective C?H cleavage by a concerted metalation‐deprotonation mechanism. 相似文献
9.
Yun-Suk Jang Dr. Michael Dieckmann Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2017,56(47):15088-15092
An enantioselective C−H amidation of phosphine oxides by using an iridium(III) catalyst bearing an atropchiral cyclopentadienyl (Cpx) ligand is reported. A very strong cooperative effect between the chiral Cpx ligand and a phthaloyl tert-leucine enabled the transformation. Matched–mismatched cases of the different acid enantiomers are shown. The amidated P-chiral arylphosphine oxides are formed in yields of up to 95 % and with excellent enantioselectivities of up to 99:1 er. Enantiospecific reduction provides access to valuable P-chiral phosphorus(III) compounds. 相似文献
10.
Mehdi ElsayedMoussa Michael Seidl Gbor Balzs Matthias Hautmann Manfred Scheer 《Angewandte Chemie (International ed. in English)》2019,58(37):12903-12907
The reactions of tetrahedral molybdenum complexes bearing unsubstituted heterodiatomic Group 15 elements, [Cp2Mo2(CO)4(μ,η2:η2‐PE)] (Cp=C5H5; E=As ( 1 ), Sb ( 2 )), with CuI halides afforded seven unprecedented neutral supramolecular assemblies. Depending on the Mo2PE units and the CuI halide, the oligomers [?{Cp2Mo2(CO)4}{μ4,η2:η2:η2:η1‐PE}?4?{CuX}{Cu(μ‐X)}?2] (E=As (X=Cl ( 3 ), Br ( 4 )); E=Sb (X=Cl ( 6 ), Br ( 7 ))) or the 1D coordination polymers [{Cp2Mo2(CO)4}{μ4,η2:η2:η1:η1‐PAs}{Cu(μ‐I)}]n ( 5 ) and [{Cp2Mo2(CO)4}{μ4,η2:η2:η2:η1‐PSb}2{Cu(μ‐X)}3]n (X=I ( 8 ), Br ( 9 )) are accessible. These solid‐state aggregates are the first and only examples featuring the organometallic heterodiatomic Mo2PE complexes 1 and 2 as linking moieties. DFT calculations demonstrate that complexes 1 and 2 present a unique class of mixed‐donor ligands coordinating to CuI centers via the P lone pair and the P?E σ‐bond, revealing an unprecedented coordination mode. 相似文献
11.
Shou‐Guo Wang Yang Liu Nicolai Cramer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18304-18308
An efficient CpxRhIII‐catalyzed enantioselective alkenyl C?H functionalization/[4+1] annulation of acryl amides and allenes is reported. The described transformation provides straightforward access to enantioenriched α,β‐unsaturated‐γ‐lactams bearing a quaternary stereocenter. The reaction operates under mild conditions, displays a broad functional‐group tolerance, and provides 2H‐pyrrol‐2‐ones with excellent selectivity of up to 97:3 er. Such scaffolds are frequently found in natural products and synthetic bioactive compounds and are of significant synthetic value. It is noteworthy that the allene serves as a one‐carbon unit in the [4+1]‐annulation. 相似文献
12.
D. V. Bonegardt I. Yu. Il’in T. S. Sukhikh N. B. Morozova 《Journal of Structural Chemistry》2017,58(5):983-988
Volatile iridium(I) complexes [Ir(cod)Cpx] (Cpx = pentamethylcyclopentadienyl Cp*, ethylcyclopentadienyl CpEt, cod = 1,5-cyclooctadiene) are synthesized and characterized by IR and NMR spectroscopy. The [Ir(cod)Cp*] complex is a solid and the [Ir(cod)CpEt] complex is a liquid (SATP). The XRD method is used to determine the structure of the [Ir(cod)Cp*] complex: chemical formula C18H27Ir, space group P21/c, a = 8,4418(2) Å, b = 9,4764(3) Å, c = 19.2682(5) Å, β = 96.128(1) °, V = 1532.61(7) Å3, Z = 4, d calc = 1.888 g/cm3, μ = 8.697 mm–1. The cyclopentadienyl ligand is η5-type coordinated; 1,5-cyclooctadiene have a cis-cis conformation and is η4-type coordinated. The thermal properties of the complexes are studied by thermogravimetry. 相似文献
13.
Several novel chiral sulfonamide ligands based on (1R,2S,4R,5S)‐1,4‐diamino‐2,5‐dimethylcyclohexane skeleton have been synthesized and their application in the enantioselective addition of diethylzinc to aldehydes was investigated in the presence of Ti(OiPr)4. The effect of ligands, temperature and the loading amount of ligands was studied. Under optimized conditions, enantioselective addition of diethylzinc with various aryl aldehydes and aliphatic aldehydes proceeded smoothly and afforded chiral secondary alcohols in up to 88% ee. 相似文献
14.
《Angewandte Chemie (International ed. in English)》2017,56(43):13237-13243
Pentaphosphaferrocenes [CpRFe(η5‐P5)] ( 1 ) and CuI halides are excellent building blocks for the formation of discrete supramolecules. Herein, we demonstrate the potential of Cu(CF3SO3) for the construction of the novel 2D polymer [{Cp*Fe(μ4,η5:1:1:1‐P5)}{Cu(CF3SO3)}]n ( 2 ) and the unprecedented nanosphere (CH2Cl2)1.4@[{CpBnFe(η5‐P5)}12{Cu(CF3SO3)}19.6] ( 3 ). The supramolecule 3 has a unique scaffold beyond the fullerene topology, with 20 copper atoms statistically distributed over the 30 vertices of an icosidodecahedron. Combinatorics was used to interpret the average disordered structure of the supramolecules. In this case, only two pairs of enantiomers with D5 and D2 symmetry are possible for bidentate bridging coordination of the triflate ligands. DFT calculations showed that differences in the energies of the isomers are negligible. The benzyl ligands enhance the solubility of 3 , enabling NMR‐spectroscopic and mass‐spectrometric investigations. 相似文献
15.
Seiya Fukagawa Yoshimi Kato Ryo Tanaka Masahiro Kojima Tatsuhiko Yoshino Shigeki Matsunaga 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1165-1169
Recent advances in CpxMIII catalysis (M=Co, Rh, Ir) have enabled a variety of enantioselective C(sp2)?H functionalization reactions, but enantioselective C(sp3)?H functionalization is still largely unexplored. We describe an asymmetric C(sp3)?H amidation of thioamides using an achiral CoIII/chiral carboxylic acid hybrid catalytic system, which provides easy and straightforward access to chiral β‐amino thiocarbonyl and β‐amino carbonyl building blocks with a quaternary carbon stereocenter. 相似文献
16.
Postsynthetic Metal and Ligand Exchange in MFU‐4l: A Screening Approach toward Functional Metal–Organic Frameworks Comprising Single‐Site Active Centers 下载免费PDF全文
Dmytro Denysenko Dr. Jelena Jelic Prof. Dr. Karsten Reuter Prof. Dr. Dirk Volkmer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8188-8199
The isomorphous partial substitution of Zn2+ ions in the secondary building unit (SBU) of MFU‐4l leads to frameworks with the general formula [MxZn(5–x)Cl4(BTDD)3], in which x≈2, M=MnII, FeII, CoII, NiII, or CuII, and BTDD=bis(1,2,3‐triazolato‐[4,5‐b],[4′,5′‐i])dibenzo‐[1,4]‐dioxin. Subsequent exchange of chloride ligands by nitrite, nitrate, triflate, azide, isocyanate, formate, acetate, or fluoride leads to a variety of MFU‐4l derivatives, which have been characterized by using XRPD, EDX, IR, UV/Vis‐NIR, TGA, and gas sorption measurements. Several MFU‐4l derivatives show high catalytic activity in a liquid‐phase oxidation of ethylbenzene to acetophenone with air under mild conditions, among which Co‐ and Cu derivatives with chloride side‐ligands are the most active catalysts. Upon thermal treatment, several side‐ligands can be transformed selectively into reactive intermediates without destroying the framework. Thus, at 300 °C, CoII‐azide units in the SBU of Co‐MFU‐4l are converted into CoII‐isocyanate under continuous CO gas flow, involving the formation of a nitrene intermediate. The reaction of CuII‐fluoride units with H2 at 240 °C leads to CuI and proceeds through the heterolytic cleavage of the H2 molecule. 相似文献
17.
Katrin Schuhen David Sieb Hubert Wadepohl Markus Enders Prof. Dr. 《无机化学与普通化学杂志》2009,635(11):1560-1567
Sodium cyclopentadienide reacts as nucleophile with 4,7‐dibromo‐2,1,3‐benzothiadiazole (BTZ) and leads to the new donor‐functionalized ligand CpBTZ. Related quinoxalyl Cp systems have been prepared using Pd‐catalyzed coupling with zincated Cp‐metal complexes. The new ligands comprise two N‐donor atoms; one of them is located in a distal position relative to the metal centre so that it cannotcoordinate in a chelating manner. With CpBTZ ligand derivatives severalmetal complexes have been synthesized. The new chromium(III) complex CpBTZCrCl2 ( 12 ) becomes upon activation an active catalyst for the polymerization of ethylene. Relying on DFT calculations and analysis of spin‐density distribution combined with paramagnetic NMR data a chelating coordination of the CpBTZ ligand is feasible in 12 . 相似文献
18.
Direct Synthesis of Chiral 3‐Arylsuccinimides by Rhodium‐Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids to Maleimides 下载免费PDF全文
Dr. Balraj Gopula Shu‐Han Yang Ting‐Shen Kuo Prof. Dr. Jen‐Chieh Hsieh Dr. Ping‐Yu Wu Dr. Julian P. Henschke Prof. Dr. Hsyueh‐Liang Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11050-11055
Chiral rhodium catalysts comprising 2,5‐diaryl‐ substituted bicyclo[2.2.1]diene ligands L1 – L10 were utilized in the enantioselective 1,4‐addition reaction of arylboronic acids to N‐substituted maleimides. In the presence of 2.5 mol % of RhI/ L2 , enantioenriched conjugate addition adducts were isolated in 72–99 % yields with 86–98 % ee. This protocol offers a convenient method to access a variety of 3‐arylsuccinimides in a highly enantioselective manner. Maleimides with readily cleavable N‐protecting groups were tolerated enabling the synthesis of useful synthetic intermediates. Pyrrolidine 4 , a biologically active compound, and pyrrolidine 5 , an ent‐precursor to an HSD‐1 inhibitor, were synthesized to demonstrate the utility of this method. 相似文献
19.
F. Mark Chadwick Basile F. E. Curchod Rosario Scopelliti Farzaneh FadaeiTirani Euro Solari Kay Severin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(6):1778-1781
Azoimidazolium dyes were used as precursors for mesoionic carbene ligands (Azo‐MICs). The properties of these ligands were examined by synthesizing RhI, AuI, and PdII complexes. Experimental (NMR, IR) and theoretical investigations show that Azo‐MICs are potent σ‐donor ligands. Yet, they feature a small singlet–triplet gap and very low‐lying LUMO levels. The unique electronic properties of Azo‐MICs allow for reversible one‐electron reductions of the metal complexes, as evidenced by cyclic voltammetry. 相似文献
20.
Dr. Yuri Tulchinsky Dr. Sebastian Kozuch Dr. Prasenjit Saha Assaf Mauda Dr. Gennady Nisnevich Dr. Mark Botoshansky Dr. Linda J. W. Shimon Prof. Mark Gandelman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7099-7110
Comprehensive studies on the coordination properties of tridentate nitrenium‐based ligands are presented. N‐heterocyclic nitrenium ions demonstrate general and versatile binding abilities to various transition metals, as exemplified by the synthesis and characterization of RhI, RhIII, Mo0, Ru0, RuII, PdII, PtII, PtIV, and AgI complexes based on these unusual ligands. Formation of nitrenium–metal bonds is unambiguously confirmed both in solution by selective 15N‐labeling experiments and in the solid state by X‐ray crystallography. The generality of N‐heterocyclic nitrenium as a ligand is also validated by a systematic DFT study of its affinity towards all second‐row transition and post‐transition metals (Y–Cd) in terms of the corresponding bond‐dissociation energies. 相似文献