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1.
Remote Control of the Planar Chirality in Peptide‐Bound Metallomacrocycles and Dynamic‐to‐Static Planar Chirality Control Triggered by Solvent‐Induced 310‐to‐α‐Helix Transitions 下载免费PDF全文
Fumihiko Mamiya Dr. Naoki Ousaka Prof. Dr. Eiji Yashima 《Angewandte Chemie (International ed. in English)》2015,54(48):14442-14446
The dynamic planar chirality in a peptide‐bound NiII‐salphen‐based macrocycle can be remotely controlled. First, a right‐handed (P)‐310‐helix is induced in the dynamic helical oligopeptides by a chiral amino acid residue far from the macrocyclic framework. The induced planar chirality remains dynamic in chloroform and acetonitrile, but is almost completely locked in fluoroalcohols as a result of the solvent‐induced transition of the peptide chains from a 310‐helix to a wider α‐helix, which freezes the rotation of the pendant peptide units around the macrocycle. 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.
Lisa Diab Jean‐Claude Daran Maryse Gouygou Eric Manoury Martine Urrutigoïty 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(12):m586-m588
The reaction of enantiomerically pure planar chiral ferrocene phosphine thioether with bis(acetonitrile)dichloridopalladium yields the title square‐planar mononuclear palladium complex as an enantiomerically pure single diastereoisomer, [PdFe(C5H5)(C20H20PS)Cl2]. The planar chirality of the ligand is retained in the complex and fully controls the central chirality on the S atom. The absolute configuration, viz. S for the planar chirality and R for the S atom, is unequivocally determined by refinement of the Flack parameter. 相似文献
4.
Jeffrey Buter Dorus Heijnen Carlos Vila Valentín Hornillos Edwin Otten Massimo Giannerini Adriaan J. Minnaard Ben L. Feringa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(11):3684-3688
A palladium‐catalyzed direct synthesis of symmetric biaryl compounds from aryl halides in the presence of tBuLi is described. In situ lithium–halogen exchange generates the corresponding aryl lithium reagent, which undergoes a homocoupling reaction with a second molecule of the aryl halide in the presence of the palladium catalyst (1 mol %). The reaction takes place at room temperature, is fast (1 h), and affords the corresponding biaryl compounds in good to excellent yields. The application of the method is demonstrated in an efficient asymmetric total synthesis of mastigophorene A. The chiral biaryl axis is constructed with an atropselectivity of 9:1 owing to catalyst‐induced remote point‐to‐axial chirality transfer. 相似文献
5.
Palladium‐Catalyzed,tert‐Butyllithium‐Mediated Dimerization of Aryl Halides and Its Application in the Atropselective Total Synthesis of Mastigophorene A 下载免费PDF全文
Jeffrey Buter Dorus Heijnen Dr. Carlos Vila Dr. Valentín Hornillos Dr. Edwin Otten Dr. Massimo Giannerini Prof. Dr. Adriaan J. Minnaard Prof. Dr. Ben L. Feringa 《Angewandte Chemie (International ed. in English)》2016,55(11):3620-3624
A palladium‐catalyzed direct synthesis of symmetric biaryl compounds from aryl halides in the presence of tBuLi is described. In situ lithium–halogen exchange generates the corresponding aryl lithium reagent, which undergoes a homocoupling reaction with a second molecule of the aryl halide in the presence of the palladium catalyst (1 mol %). The reaction takes place at room temperature, is fast (1 h), and affords the corresponding biaryl compounds in good to excellent yields. The application of the method is demonstrated in an efficient asymmetric total synthesis of mastigophorene A. The chiral biaryl axis is constructed with an atropselectivity of 9:1 owing to catalyst‐induced remote point‐to‐axial chirality transfer. 相似文献
6.
RhCl(PPh3)3‐catalyzed [4+2] intramolecular cycloaddition of optically active axially chiral allene‐dienes afforded cis‐fused [3.4.0]‐bicyclic products with three chiral centers in good yields with an excellent chemo‐ and diastereoselectivity. A pair of enantiomers of such products was generated highly selectively from both enantiomers of starting allene‐dienes, indicating that the axial chirality dictated the absolute configurations of the three in situ generated chiral centers with a very high efficiency of chirality transfer. 相似文献
7.
Combining Organocatalysis with Central‐to‐Axial Chirality Conversion: Atroposelective Hantzsch‐Type Synthesis of 4‐Arylpyridines 下载免费PDF全文
Ophélie Quinonero Marion Jean Dr. Nicolas Vanthuyne Prof. Dr. Christian Roussel Dr. Damien Bonne Prof. Dr. Thierry Constantieux Prof.Dr. Cyril Bressy Dr. Xavier Bugaut Prof. Dr. Jean Rodriguez 《Angewandte Chemie (International ed. in English)》2016,55(4):1401-1405
Suitably substituted enantioenriched 4‐aryl‐1,4‐dihydro‐pyridines prepared by an organocatalytic enantioselective Michael addition were oxidized with MnO2 into axially chiral 4‐arylpyridines with central‐to‐axial chirality conversion. Moderate to complete percentages (cp) were observed, and a model for the conversion of chirality is discussed. 相似文献
8.
A series of C2-symmetrical chiral 2,5-bis (4′-alkyloxazolin-2-yl) thiophenes (thiobox) have been synthesized from thiophene-2,5-dicarboxylic acid by sequential amidation with a chiral ethanolamine,conversion of hydroxyl to chloro group, and base-promoted oxazoline ring formation.As demonstrated by (-)-2,5-bis[4′-(S)-isopropyloxazolin-2′-yl] thiophene,these thiobox systems exhibited remarkable chirality recognition of 1,1′-bi-2-naphthol giving rise to pronounced shifts in the ^1H NMR signals of the latter axial chiral compound at the positions of C-3,C-4,C-5,and C-8. 相似文献
9.
Min Deng Nishya F. M. Mukthar Nathan D. Schley Gaël Ung 《Angewandte Chemie (International ed. in English)》2020,59(3):1228-1231
The synthesis of chiral C1‐symmetrical copper(I) complexes supported by chiral carbene ligands is described. These complexes are yellow emitters with modest quantum yields. Circularly polarized luminescence (CPL) spectra show a polarized emission band with dissymmetry factors |glum|=1.2×10?3. These complexes are the first reported examples of molecular copper(I) complexes exhibiting circularly polarized luminescence. In contrast with most CPL‐emitting molecules, which possess either helical or axial chirality, the results presented show that simple chiral architectures are suitable for CPL emission and unlock new synthetic possibilities. 相似文献
10.
Genki Namba Yuki Mimura Prof. Yoshitane Imai Dr. Ryo Inoue Prof. Yasuhiro Morisaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):14871-14877
Optically active X-shaped molecules based on the planar chiral [2.2]paracyclophane building block were prepared, in which di(methoxy)terphenyl units were stacked on the central benzene rings. At 25 °C, anisolyl rings freely rotate in solution, while in the crystal form, they are fixed by intramolecular CH–π interactions, thereby leading to the expression of the axial chirality, i.e., propeller chirality was exhibited by the planar chiral [2.2]paracyclophane moiety. The X-shaped molecule exhibited good circularly polarized luminescence (CPL) profiles with moderate ΦPL and a large glum value in the order of 10−3 at 25 °C, in solution. In contrast, at −120 °C, dual CPL emission with opposite signs was observed. According to the theoretical studies, the rotary motion of the anisolyl units is suppressed in the excited states, and so emission from two isomers could be observed. These results demonstrate that the axial chirality was controlled by the planar chirality, leading ultimately to propeller chirality. 相似文献
11.
Lingheng Kong Xi Han Song Liu Yun Zou Yu Lan Xingwei Li 《Angewandte Chemie (International ed. in English)》2020,59(18):7188-7192
Axial‐to‐central chirality transfer is an important strategy to construct chiral centers, where the axially chiral reagents are mostly limited to atropomerically stable ones. Reported herein is a RhIII‐catalyzed enantioselective spiroannulative synthesis of nitrones. The coupling proceeds via C?H arylation to give an atropomerically metastable biaryl, followed by intramolecular dearomative trapping under oxidative conditions with high degree of chirality transfer. 相似文献
12.
Christophe Michon 《Tetrahedron》2008,64(51):11756-11762
Planar chiral arene chromium complexes with enyne bond gave stereoselectively axial biaryl chromium complexes by gold(I) catalyzed cycloisomerization in good yields. Arene chromium complexes with enyne bonds were treated with triphenylphosphine gold bis(trifluoromethanesulfonyl)imidate in methylene chloride to give anti-biaryl monochromium complexes without formation of stereoisomers. 相似文献
13.
Bei‐Bei Zhan Lei Wang Jun Luo Xu‐Feng Lin Bing‐Feng Shi 《Angewandte Chemie (International ed. in English)》2020,59(9):3568-3572
A simple and ubiquitously present group, free amine, is used as a directing group to synthesize axially chiral biaryl compounds by PdII‐catalyzed atroposelective C?H olefination. A broad range of axially chiral biaryl‐2‐amines can be obtained in good yields with high enantioselectivities (up to 97 % ee). Chiral spiro phosphoric acid (SPA) proved to be an efficient ligand and the loading could be reduced to 1 mol % without erosion of enantiocontrol in gram‐scale synthesis. The resulting axially chiral biaryl‐2‐amines also provide a platform for the synthesis of a set of chiral ligands. 相似文献
14.
Fei Ye Dr. Zhan‐Jiang Zheng Wen‐Hui Deng Long‐Sheng Zheng Dr. Yuan Deng Prof. Chun‐Gu Xia Prof. Dr. Li‐Wen Xu 《化学:亚洲杂志》2013,8(9):2242-2253
In this work, we have successfully synthesized a new family of chiral Schiff base–phosphine ligands derived from chiral binaphthol (BINOL) and chiral primary amine. The controllable synthesis of a novel hexadentate and tetradentate N,O,P ligand that contains both axial and sp3‐central chirality from axial BINOL and sp3‐central primary amine led to the establishment of an efficient multifunctional N,O,P ligand for copper‐catalyzed conjugate addition of an organozinc reagent. In the asymmetric conjugate reaction of organozinc reagents to enones, the polymer‐like bimetallic multinuclear Cu? Zn complex constructed in situ was found to be substrate‐selective and a highly excellent catalyst for diethylzinc reagents in terms of enantioselectivity (up to >99 % ee). More importantly, the chirality matching between different chiral sources, C2‐axial binaphthol and sp3‐central chiral phosphine, was crucial to the enantioselective induction in this reaction. The experimental results indicated that our chiral ligand (R,S,S)‐ L1 ‐ and (R,S)‐ L4 ‐based bimetallic complex catalyst system exhibited the highest catalytic performance to date in terms of enantioselectivity and conversion even in the presence of 0.005 mol % of catalyst (S/C=20 000, turnover number (TON)=17 600). We also studied the tandem silylation or acylation of enantiomerically enriched zinc enolates that formed in situ from copper‐ L4 ‐complex‐catalyzed conjugate addition, which resulted in the high‐yield synthesis of chiral silyl enol ethers and enoacetates, respectively. Furthermore, the specialized structure of the present multifunctional N,O,P ligand L1 or L4 , and the corresponding mechanistic study of the copper catalyst system were investigated by 31P NMR spectroscopy, circular dichroism (CD), and UV/Vis absorption. 相似文献
15.
Krzysztof Ejsmont Janusz Kyzio Ewa Nowakowska Jacek Zaleski 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):93-94
The title compound, C23H28O2, was obtained from the reaction of acetone with meta‐cresol. The molecular structure consists of two identical subunits which are nearly perpendicular to each other. The oxygen‐containing rings are not planar and the molecule is chiral. The crystal structure consists of chains of molecules of the same chirality arranged along the [010] axis. 相似文献
16.
Remote Central‐to‐Axial Chirality Conversion: Direct Atroposelective Ester to Biaryl Transformation 下载免费PDF全文
Achim Link Prof. Dr. Christof Sparr 《Angewandte Chemie (International ed. in English)》2018,57(24):7136-7139
A strategy for the remote central‐to‐axial chirality conversion by simultaneous planarization of an encoding and a transient stereocenter is presented. Based on a diastereoselective double addition of a chiral 1,5‐bifunctional organomagnesium alkoxide reagent to a broad range of aryl ester substrates, axially chiral biaryls are directly obtained upon in situ reduction. Various structurally distinct atropisomeric biaryl silanes that serve as valuable chiral biaryl anion surrogates are accessible in one step with e.r. values of up to 98:2. 相似文献
17.
Dr. Li Ma Dr. Rizhe Jin Dr. Zheng Bian Dr. Chuanqing Kang Yu Chen Prof. Jingwei Xu Prof. Lianxun Gao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13168-13172
An atropisomeric biaryl molecule with a given absolute configuration could present two opposite helical conformations through the rotation around C? C single bond. To the best of our knowledge, the biaryl system is the simplest helical inversion model apart from stereomutation between two enantiomers. Herein, we first report such true helical inversion phenomena of biaryl compounds. Two [MoVIO2(L)]‐type complexes, in which L is a tridentate dioxoanionic pyridine O,N,O‐ligand, are coalesced on the 2,2′,3,3′‐positions of an (R)‐1,1′‐binaphthyl unit and an intramolecular dioxo bridge is formed by two Mo?O???Mo interactions. Exterior strong donors can coordinate to molybdenum to interrupt this dioxo bridge and inversions from negative to positive chirality are explicitly observed by circular dichroism spectroscopy, consistent with single‐crystal X‐ray diffraction analyses. 相似文献
18.
Dr. Kun Liu Xiangfei Wu Dr. S. B. Jennifer Kan Dr. Seiji Shirakawa Prof. Dr. Keiji Maruoka 《化学:亚洲杂志》2013,8(12):3214-3221
Catalytic asymmetric synthesis of axially chiral o‐iodoanilides and o‐tert‐butylanilides as useful chiral building blocks was achieved by means of binaphthyl‐modified chiral quaternary ammonium‐salt‐catalyzed N‐alkylations under phase‐transfer conditions. The synthetic utility of axially chiral products was demonstrated in various transformations. For example, axially chiral N‐allyl‐o‐iodoanilide was transformed to 3‐methylindoline by means of radical cyclization with high chirality transfer from axial chirality to C‐centered chirality. Furthermore, stereochemical information on axial chirality in o‐tert‐butylanilides could be used as a template to control the stereochemistry of subsequent transformations. The transition‐state structure of the present phase‐transfer reaction was discussed on the basis of the X‐ray crystal structure of ammonium anilide, which was prepared from binaphthyl‐modified chiral ammonium bromide and o‐iodoanilide. The chiral tetraalkylammonium bromide as a phase‐transfer catalyst recognized the steric difference between the ortho substituents on anilide to obtain high enantioselectivity. The size and structural effects of the ortho substituents on anilide were investigated, and a wide variety of axially chiral anilides that possess various functional groups could be synthesized with high enantioselectivities. This method is the only general way to access a variety of axially chiral anilides in a highly enantioselective fashion reported to date. 相似文献
19.
Enantiopure Ferrocene‐Based Planar‐Chiral Iridacycles: Stereospecific Control of Iridium‐Centred Chirality 下载免费PDF全文
Ross A. Arthurs Dr. Muhammad Ismail Christopher C. Prior Dr. Vasily S. Oganesyan Dr. Peter N. Horton Dr. Simon J. Coles Dr. Christopher J. Richards 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3065-3072
Reaction of [IrCp*Cl2]2 with ferrocenylimines (Fc=NAr, Ar=Ph, p‐MeOC6H4) results in ferrocene C?H activation and the diastereoselective synthesis of half‐sandwich iridacycles of relative configuration Sp*,RIr*. Extension to (S)‐2‐ferrocenyl‐4‐(1‐methylethyl)oxazoline gave highly diastereoselective control over the new elements of planar chirality and metal‐based pseudo‐tetrahedral chirality, to give both neutral and cationic half‐sandwich iridacycles of absolute configuration Sc,Sp,RIr. Substitution reactions proceed with retention of configuration, with the planar chirality controlling the metal‐centred chirality through an iron–iridium interaction in the coordinatively unsaturated cationic intermediate. 相似文献
20.
Dynamic Chirality Control of tropos DPCB‐digold Skeleton by Chiral Binaphthyldicarboxylate 下载免费PDF全文
Prof. Dr. Shigekazu Ito Masaki Nanko Tomokazu Shinozaki Masafumi Kojima Dr. Kohsuke Aikawa Prof. Dr. Koichi Mikami 《化学:亚洲杂志》2016,11(6):823-827
The planar 3,4‐diphosphinidenecyclobutene (DPCB) can be remarkably twisted into a C2‐type helical structure by dual coordination of a AuCl moiety. A prompt chirality control of the twisted DPCB skeleton ligated by the digold units affords the enantiopure structure by exchanging the chloride ligands for chiral [1,1′‐binaphthalene]‐2,2′‐dicarboxylate. The chirality of the diaurated 2,2′‐bis(diphenylphosphanyl)‐1,1′‐biphenyl (BIPHEP) system can be controlled prior to that of DPCB. Mixing of a DPCB‐bis(chlorogold) complex with the chiral silver salt dynamically leads to a single diastereomer, which was characterized by the 31P NMR spectrum and the CD couplet patterns in the visible (DPCB) area. The absolute configuration of the singly induced helical structure was assigned by the theoretical CD spectra determined by TD‐DFT calculations. Intramolecular alkoxycyclization of hexa‐4,5‐dien‐1‐ol catalyzed by the asymmetric DPCB‐digold structure were also attempted. 相似文献