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1.
Chiral Palladacycle Catalysts Generated on a Single‐Handed Helical Polymer Skeleton for Asymmetric Arylative Ring Opening of 1,4‐Epoxy‐1,4‐dihydronaphthalene
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Dr. Takeshi Yamamoto Yuto Akai Prof. Dr. Michinori Suginome 《Angewandte Chemie (International ed. in English)》2014,53(47):12785-12788
Post‐polymerization C? H activation of poly(quinoxaline‐2,3‐diyl)‐based helically chiral phosphine ligands (PQXphos) with palladium(II) acetate afforded chiral phosphapalladacycles quantitatively. In situ generated palladacycles exhibited enantioselectivities up to 94 % ee in the palladium‐catalyzed asymmetric ring‐opening arylation of 1,4‐epoxy‐1,4‐dihydronaphthalenes with arylboronic acids. 相似文献
2.
Lian‐Feng Fan Shi‐Wei Luo Shu‐Sen Chen Tian‐Ci Wang Pu‐Sheng Wang Liu‐Zhu Gong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):16962-16966
Branched selectivity in asymmetric allylic C?H alkylation is enabled by using 2‐acylimidazoles as nucleophiles in the presence of a chiral phosphoramidite‐palladium catalyst. A wide range of terminal alkenes, including 1,4‐dienes and allylarenes, are nicely tolerated and provide chiral 2‐acylimidazoles in moderate to high yields and with high levels of regio‐, and enantio‐, and E/Z‐selectivities. Mechanistic studies using density‐functional theory calculations suggest a nucleophile‐coordination‐enabled inner‐sphere attack mode for the enantioselective carbon–carbon bond‐forming event. 相似文献
3.
Access to P‐ and Axially Chiral Biaryl Phosphine Oxides by Enantioselective CpxIrIII‐Catalyzed C−H Arylations
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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
4.
Asymmetric Desymmetrization via Metal‐Free C−F Bond Activation: Synthesis of 3,5‐Diaryl‐5‐fluoromethyloxazolidin‐2‐ones with Quaternary Carbon Centers
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Junki Tanaka Satoru Suzuki Etsuko Tokunaga Prof. Dr. Günter Haufe Prof. Dr. Norio Shibata 《Angewandte Chemie (International ed. in English)》2016,55(32):9432-9436
We disclose the first asymmetric activation of a non‐activated aliphatic C?F bond in which a conceptually new desymmetrization of 1,3‐difluorides by silicon‐induced selective C?F bond scission is a key step. The combination of a cinchona alkaloid based chiral ammonium bifluoride catalyst and N,O‐bis(trimethylsilyl)acetoamide (BSA) as the silicon reagent enabled the efficient catalytic cycle of asymmetric Csp3?F bond cleavage under mild conditions with high enantioselectivities. The ortho effect of the aryl group at the prostereogenic center is remarkable. This concept was applied for the asymmetric synthesis of promising agrochemical compounds, 3,5‐diaryl‐5‐fluoromethyloxazolidin‐2‐ones bearing a quaternary carbon center. 相似文献
5.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(24):6912-6916
Inspired by the unique character of enzymes, we developed novel chiral SPO (secondary‐phosphine‐oxide) ligand (SPO‐Wudaphos) which can enter into both ion pair and H‐bond noncovalent interactions. The novel chiral SPO‐Wudaphos exhibited excellent results in the asymmetric hydrogenation of α‐methylene‐γ‐keto carboxylic acids, affording the chiral γ‐keto acids with up to over 99 % ee . A series of control experiments and DFT calculations were conducted to illustrate the critical roles of both the ion pair and H‐bond noncovalent interactions. 相似文献
6.
Density functional theory calculations are used to study the reaction mechanism and origins of high stereoselectivity in chiral guanidine‐catalyzed asymmetric 1,4‐addition of 5H‐oxazol‐4‐ones. The reaction involves proton abstraction of 5H‐oxazol‐4‐one, C—C bond formation, and proton transfer. N1 atom of chiral guanidine exchanges its character as base and acid to activate 5H‐oxazol‐4‐one and to facilitate the product formation. The role of N2—H2 is not only H‐bond donor for 5H‐oxazol‐4‐one but also electron accepter for N1. The enantioselectivity related with rate‐limiting step 1 and Z/E selectivity determined in step 2 are primarily influenced by a five to six‐membered ring link in the backbone of chiral guanidine. The reaction proceeds along the favorable path with smaller rotations of the linked bonds. The enantioselectivity is improved with guanidine involving an electron‐deficient and bulky substituent. With methyl ether‐protected hydroxy in structure, the catalytic ability and enantioselective control of guanidine are extraordinarily low, affording the opposite enantiomer as major product. Z‐isomers are preferred in all cases. © 2013 Wiley Periodicals, Inc. 相似文献
7.
Stereospecific Synthesis of α‐ and β‐Hydroxyalkyl P‐Stereogenic Phosphine–Boranes and Functionalized Derivatives: Evidence of the PO Activation in the BH3‐Mediated Reduction
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Sébastien Lemouzy Dr. Duc Hanh Nguyen Valentine Camy Marion Jean Dr. David Gatineau Dr. Laurent Giordano Dr. Jean‐Valère Naubron Dr. Nicolas Vanthuyne Dr. Damien Hérault Prof. Gérard Buono 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15607-15621
Access to hydroxy‐functionalized P‐chiral phosphine–boranes has become an important field in the synthesis of P‐stereogenic compounds used as ligands in asymmetric catalysis. A family of optically pure α and β‐hydroxyalkyl tertiary phosphine–boranes has been prepared by using a three‐step procedure from readily accessible enantiopure adamantylphosphinate, obtained by semi‐preparative HPLC on multigram scale. Firstly, a two‐step one‐pot transformation affords the enantiopure hydroxyalkyl tertiary phosphine oxides in good yields and enantioselectivities. The third step, BH3‐mediated reduction, allows the formation of the desired phosphine–boranes with excellent stereospecifity. The mechanistic study of this reduction provides new evidence to elucidate the crucial role of the pendant hydroxy group and the subsequent activation of the P?O bond by the boron atom. 相似文献
8.
Desymmetrization of 1,4‐Pentadien‐3‐ol by the Asymmetric 1,3‐Dipolar Cycloaddition of Azomethine Imines
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Mari Yoshida Naotaro Sassa Tomomitsu Kato Dr. Shuhei Fujinami Dr. Takahiro Soeta Prof. Dr. Katsuhiko Inomata Prof. Dr. Yutaka Ukaji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(7):2058-2064
Desymmetrization of the divinyl carbinol 1,4‐pentadien‐3‐ol was accomplished by the asymmetric 1,3‐dipolar cycloaddition of azomethine imines based on a magnesium‐mediated, multinucleating chiral reaction system utilizing diisopropyl (R,R)‐tartrate as the chiral auxiliary. The corresponding optically active trans‐pyrazolidines, each with three contiguous stereogenic centers, were obtained with excellent regio‐, diastereo‐, and enantioselectivity, with results as high as 99 % ee. This reaction was shown to be applicable to both aryl‐ and alkyl‐substituted azomethine imines. The use of a catalytic amount of diisopropyl (R,R)‐tartrate was also effective when accompanied by the addition of MgBr2. 相似文献
9.
Chiral Carboxylic Acid Enabled Achiral Rhodium(III)‐Catalyzed Enantioselective C−H Functionalization
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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
10.
Lei Peng Kai Li Chuandong Xie Shan Li Da Xu Wenling Qin Hailong Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17359-17364
A chiral Brønsted base catalyzed asymmetric annulation of ortho‐alkynylanilines has been developed to access axially chiral naphthyl‐C2‐indoles via vinylidene ortho‐quinone methide (VQM) intermediates. This strategy provides a unique organocatalytic atroposelective route to axially chiral aryl‐C2‐indole skeletons with excellent enantioselectivity and functional‐group tolerance. This transformation was applicable to decagram‐scale preparation (50.0 g) with perfect enantioselectivity through simple recrystallization. Moreover, the utility of this reaction was demonstrated by a variety of transformations towards chiral naphthyl‐C2‐indoles for a series of carbon–heteroatom bond formations. Furthermore, the prepared axially chiral naphthyl‐C2‐indoles were applied as a chiral skeleton for organocatalytic aza‐Baylis–Hillman reaction and asymmetric formal [4+2] tandem cyclization to give the corresponding adducts in high yields with improved enantioselectivity and diastereoselectivity. 相似文献
11.
Asymmetric P−C Bond Formation: Diastereoselective Synthesis of Adjacent P,C‐Stereogenic Allylic Phosphorus Compounds
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A novel catalytic asymmetric P?C bond formation between phosphinates/phosphine oxide and allylic carbonates was developed. This methodology could not only afford a variety of functionalized adjacent P,C‐stereogenic phosphorus compounds in high yields with high regio‐ and diastereoselectivities but also provide an alternative strategy to access enantiomerically enriched (SP)‐phosphinates through kinetic resolution. 相似文献
12.
Asymmetric Radical–Radical Cross‐Coupling through Visible‐Light‐Activated Iridium Catalysis
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Chuanyong Wang Jie Qin Xiaodong Shen Radostan Riedel Dr. Klaus Harms Prof. Dr. Eric Meggers 《Angewandte Chemie (International ed. in English)》2016,55(2):685-688
Combining single electron transfer between a donor substrate and a catalyst‐activated acceptor substrate with a stereocontrolled radical–radical recombination enables the visible‐light‐driven catalytic enantio‐ and diastereoselective synthesis of 1,2‐amino alcohols from trifluoromethyl ketones and tertiary amines. With a chiral iridium complex acting as both a Lewis acid and a photoredox catalyst, enantioselectivities of up to 99 % ee were achieved. A quantum yield of <1 supports the proposed catalytic cycle in which at least one photon is needed for each asymmetric C? C bond formation mediated by single electron transfer. 相似文献
13.
Jompol Thongpaen Romane Manguin Olivier Basl 《Angewandte Chemie (International ed. in English)》2020,59(26):10242-10251
The asymmetric functionalization of C?H bond is a particularly valuable approach for the production of enantioenriched chiral organic compounds. Chiral N‐heterocyclic carbene (NHC) ligands have become ubiquitous in enantioselective transition‐metal catalysis. Conversely, the use of chiral NHC ligands in metal‐catalyzed asymmetric C?H bond functionalization is still at an early stage. This minireview highlights all the developments and the new advances in this rapidly evolving research area. 相似文献
14.
Rhodium‐Catalyzed Enantioselective Intramolecular CH Silylation for the Syntheses of Planar‐Chiral Metallocene Siloles
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Dr. Qing‐Wei Zhang Kun An Li‐Chuan Liu Yuan Yue Prof. Dr. Wei He 《Angewandte Chemie (International ed. in English)》2015,54(23):6918-6921
Reported herein is the rhodium‐catalyzed enantioselective C? H bond silylation of the cyclopentadiene rings in Fe and Ru metallocenes. Thus, in the presence of (S)‐TMS‐Segphos, the reactions took place under very mild conditions to afford metallocene‐fused siloles in good to excellent yields and with ee values of up to 97 %. During this study it was observed that the steric hindrance of chiral ligands had a profound influence on the reactivity and enantioselectivity of the reaction, and might hold the key to accomplishing conventionally challenging asymmetric C? H silylations. 相似文献
15.
Ze‐Hun Cao Yu‐Hao Wang Subarna Jyoti Kalita Uwe Schneider Yi‐Yong Huang 《Angewandte Chemie (International ed. in English)》2020,59(5):1884-1890
Unprecedented phosphine‐catalyzed [4+1] cycloadditions of allenyl imides have been discovered using various N‐based substrates including methyl ketimines, enamines, and a primary amine. These transformations provide a one‐pot access to cyclopentenoyl enamines and imines, or (chiral) γ‐lactams through two geminal C?C bond or two C?N bond formations, respectively. Several P‐based key intermediates including a 1,4‐(bis)electrophilic α,β‐unsaturated ketenyl phosphonium species have been detected by 31P NMR and HRMS analyses, which shed light on the postulated catalytic cycle. The synthetic utility of this new chemistry has been demonstrated through a gram‐scaling up of the catalytic reaction as well as regioselective hydrogenation and double condensation to form cyclopentanoyl enamines and fused pyrazole building blocks, respectively. 相似文献
16.
Honghe Li Xiaoqiang Yan Jitan Zhang Weicong Guo Jijun Jiang Jun Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(20):6804-6808
The first enantioselective Satoh–Miura‐type reaction is reported. A variety of C?N axially chiral N‐aryloxindoles have been enantioselectively synthesized by an asymmetric rhodium‐catalyzed dual C?H activation reaction of N‐aryloxindoles and alkynes. High yields and enantioselectivities were obtained (up to 99 % yield and up to 99 % ee). To date, it is also the first example of the asymmetric synthesis of C?N axially chiral compounds by such a C?H activation strategy. 相似文献
17.
Direct Synthesis of Benzofuro[2,3‐b]pyrroles through a Radical Addition/[3,3]‐Sigmatropic Rearrangement/Cyclization/Lactamization Cascade
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Dr. Masafumi Ueda Yuta Ito Yuki Ichii Maiko Kakiuchi Hiroko Shono Prof. Dr. Okiko Miyata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(22):6763-6770
A straightforward synthetic method for the construction of benzofuro[2,3‐b]pyrrol‐2‐ones by a novel domino reaction through a radical addition/[3,3]‐sigmatropic rearrangement/cyclization/lactamization cascade has been developed. The domino reaction of O‐phenyl‐conjugated oxime ether with an alkyl radical allows the construction of two heterocycles with three stereogenic centers as a result of the formation of two C?C bonds, a C?O bond, and a C?N bond in a single operation, leading to pyrrolidine‐fused dihydrobenzofurans, which are not easily accessible by existing synthetic methods. Furthermore, asymmetric synthesis of benzofuro[2,3‐b]pyrrol‐2‐one derivatives through a diastereoselective radical addition reaction to a chiral oxime ether was also developed. 相似文献
18.
Kostiantyn O. Marichev Kan Wang Kuiyong Dong Nicole Greco Lyne A. Massey Yongming Deng Hadi Arman Michael P. Doyle 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16334-16338
The all‐cis stereoisomers of tetrasubstituted azetidine‐2‐carboxylic acids and derivatives that possess three chiral centers have been prepared in high yield and stereocontrol from silyl‐protected Z‐γ‐substituted enoldiazoacetates and imido‐sulfur ylides by asymmetric [3+1]‐cycloaddition using chiral sabox copper(I) catalysis followed by Pd/C catalytic hydrogenation. Hydrogenation of the chiral p‐methoxybenzyl azetine‐2‐carboxylates occurs with both hydrogen addition to the C=C bond and hydrogenolysis of the ester. 相似文献
19.
Jingzhao Xia Dr. Guoqiang Yang Ruijing Zhuge Prof. Dr. Yangang Liu Prof. Dr. Wanbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18354-18357
An iridium‐catalyzed asymmetric hydrogenation of unfunctionalized exocyclic C=C bonds was performed by using an axially flexible chiral phosphine–oxazoline ligand, providing the desired chiral 1‐benzyl‐2,3‐dihydro‐1H‐indene products with up to 98 % ee (enantiomeric excess). This represents the first general hydrogenation of unfunctionalized exocyclic olefins with high selectivity reported thus far. The additive acetate ion plays an important role in the reaction's high enantioselectivity. The chiral product can be further transformed into key intermediates required for the synthesis of an important insecticide and a drug compound. 相似文献
20.
Yao Ge Dr. Zhaobin Han Dr. Zheng Wang Chen‐Guo Feng Qian Zhao Guo‐Qiang Lin Prof. Dr. Kuiling Ding 《Angewandte Chemie (International ed. in English)》2018,57(40):13140-13144
The first asymmetric hydrogenation of 3‐ylidenephthalides has been developed using the IrI complex of a spiro[4,4]‐1,6‐nonadiene‐based phosphine‐oxazoline ligand (SpinPHOX) as the catalyst, affording a wide variety of chiral 3‐substituted phthalides in excellent enantiomeric excesses (up to 98 % ee). The utility of the protocol has been demonstrated in the asymmetric synthesis of chiral drugs NBP and BZP precursor, as well as the natural products chuangxinol and typhaphthalide. 相似文献