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1.
Enantioselective Copper‐Catalyzed Decarboxylative Propargylic Alkylation of Propargyl β‐Ketoesters with a Chiral Ketimine P,N,N‐Ligand 下载免费PDF全文
Fu‐Lin Zhu Yuan Zou De‐Yang Zhang Ya‐Hui Wang Xin‐Hu Hu Song Chen Prof. Dr. Jie Xu Prof. Dr. Xiang‐Ping Hu 《Angewandte Chemie (International ed. in English)》2014,53(5):1410-1414
The first enantioselective copper‐catalyzed decarboxylative propargylic alkylation has been developed. Treatment of propargyl β‐ketoesters with a catalyst, prepared in situ from [Cu(CH3CN)4BF4] and a newly developed chiral tridentate ketimine P,N,N‐ligand under mild reaction conditions, generates β‐ethynyl ketones in good yields and with high enantioselectivities without requiring the pregeneration of ketone enolates. This new process provides facile access to a range of chiral β‐ethynyl ketones in a highly enantioenriched form. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(35):10587-10592
The enantioselective N‐alkylation of indole and its derivatives with aldimines is efficiently catalyzed by a zinc‐ProPhenol dinuclear complex under mild conditions to afford N‐alkylated indole derivatives in good yield (up to 86 %) and excellent enantiomeric ratio (up to 99.5:0.5 e.r.). This method tolerates a wide array of indoles, as well as pyrrole and carbazole, to afford the corresponding N‐alkylation products. The reaction can be run on a gram scale with reduced catalyst loading without impacting the efficiency. The chiral aminals were further elaborated into various chiral polyheterocyclic derivatives. The surprising stability of the chiral N‐alkylation products will open new windows for asymmetric catalysis and medicinal chemistry. 相似文献
3.
Chiral N‐Heterocyclic Carbene Ligands Bearing a Pyridine Moiety for the Copper‐Catalyzed Alkylation of N‐Sulfonylimines with Dialkylzinc Reagents 下载免费PDF全文
Dr. Takahiro Soeta Tomohiro Ishizaka Yuta Tabatake Prof. Dr. Yutaka Ukaji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16773-16778
Amino acid‐derived chiral imidazolium salts, each bearing a pyridine ring, were developed as N‐heterocyclic carbene ligands. The copper‐catalyzed asymmetric alkylation of various N‐sulfonylimines with dialkylzinc reagents in the presence of these chiral imidazolium salts afforded the corresponding alkylated products with high enantioselectivity (up to 99 % ee). The addition of HMPA to the reaction mixture as a co‐solvent is critical in terms of chemical yield and enantioselectivity. A wide range of N‐sulfonylimines and dialkylzinc reagents were found to be applicable to this reaction. 相似文献
4.
Dr. Jihye Park Hyunjung Oh Saegun Kim Kyuneun Kim Dr. Ashok Kumar Pandey Sang Hoon Han Dr. Soo Bong Han Prof. Dr. In Su Kim 《Angewandte Chemie (International ed. in English)》2018,57(39):12737-12740
The ability to alkylate pyridines and quinolines is important for their further development as pharmaceuticals and agrochemicals, and for other purposes. Herein we describe the unprecedented reductive alkylation of pyridine and quinoline N‐oxides using Wittig reagents. A wide range of pyridine and quinoline N‐oxides were converted into C2‐alkylated pyridines and quinolines with excellent site selectivity and functional‐group compatibility. Sequential C?H functionalization reactions of pyridine and quinoline N‐oxides highlight the utility of the developed method. Detailed labeling experiments were performed to elucidate the mechanism of this process. 相似文献
5.
Mukesh Pappoppula Flavio S. P. Cardoso B. Owen Garrett Prof. Aaron Aponick 《Angewandte Chemie (International ed. in English)》2015,54(50):15202-15206
A highly enantioselective copper‐catalyzed alkynylation of quinolinium salts is reported. The reaction employs StackPhos, a newly developed imidazole‐based chiral biaryl P,N ligand, and copper bromide to effect a three‐component reaction between a quinoline, a terminal alkyne, and ethyl chloroformate. Under the reaction conditions, the desired products are delivered in high yields with ee values of up to 98 %. The transformation tolerates a wide range of functional groups with respect to both the alkyne and the quinoline starting materials and the products are easily transformed into useful synthons. Efficient, enantioselective syntheses of the tetrahydroquinoline alkaloids (+)‐galipinine, (+)‐angustureine, and (?)‐cuspareine are reported. 相似文献
6.
Ya Chen Yixiao Pan Yan‐Mei He Qing‐Hua Fan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):16987-16990
A highly enantioselective iridium‐ or ruthenium‐catalyzed intermolecular reductive amination/asymmetric hydrogenation relay with 2‐quinoline aldehydes and aromatic amines has been developed. A broad range of sterically tunable chiral N,N′‐diaryl vicinal diamines were obtained in high yields (up to 95 %) with excellent enantioselectivity (up to >99 % ee). The resulting chiral diamines could be readily transformed into sterically hindered chiral N‐heterocyclic carbene (NHC) precursors, which are otherwise difficult to access. The usefulness of this synthetic approach was further demonstrated by the successful application of one of the chiral vicinal diamines and chiral NHC ligands in a transition‐metal‐catalyzed asymmetric Suzuki–Miyaura cross‐coupling reaction and asymmetric ring‐opening cross‐metathesis, respectively. 相似文献
7.
Tomohiko Shirai Yasunori Yamamoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(34):10032-10035
Highly enantioselective cationic iridium‐catalyzed hydroarylation of bicycloalkenes, by carbonyl‐directed C H bond cleavage, was accomplished using a newly synthesized sulfur‐linked bis(phosphoramidite) ligand (S‐Me‐BIPAM). The reaction provides alkylated acetophenone or benzamide derivatives in moderate to excellent yields and good to excellent enantioselectivities. Notably, the hydroarylation reaction of 2‐norbornene with N,N‐dialkylbenzamide proceeds with excellent enantioselectivity (up to 99 % ee) and high selectivity for the mono‐ortho‐alkylation product. 相似文献
8.
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
9.
Mukesh Pappoppula Prof. Aaron Aponick 《Angewandte Chemie (International ed. in English)》2015,54(52):15827-15830
An enantioselective total synthesis of martinellic acid is described. The pyrroloquinoline alkaloid core is efficiently prepared from a quinoline, employing a method which relies on a newly developed Cu‐catalyzed enantioselective alkynylation using the chiral imidazole‐based biaryl P,N ligand StackPhos to establish the absolute stereochemistry. The remaining carbon atoms are then installed by means of a diastereoselective Pd‐catalyzed decarboxylative allylation and the synthesis is completed after straightforward functional‐group manipulation. This new synthetic method enables the most concise enantioselective synthesis of this important class of molecules to date. 相似文献
10.
Luke S. Hutchings‐Goetz Chao Yang James W. B. Fyfe Thomas N. Snaddon 《Angewandte Chemie (International ed. in English)》2020,59(40):17556-17564
We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α‐alkylation. This provides products containing indole‐bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent of the N‐substituent. This led to concise syntheses of (?)‐akuammicine and (?)‐strychnine. In the second case, the poor performance of ortho‐substituted cinnamyl electrophiles in the enantioselective cooperative isothiourea/Ir catalyzed α‐alkylation was overcome by appropriate substituent choice, leading to enantioselective syntheses of (+)‐chelidonine, (+)‐norchelidonine, and (+)‐chelamine. 相似文献
11.
Chen‐Xi Ye Shuming Chen Feng Han Xiulan Xie Sergei Ivlev K. N. Houk Eric Meggers 《Angewandte Chemie (International ed. in English)》2020,59(32):13552-13556
A transformation of fluxional into configurationally stable axially chiral N‐arylpyrroles was achieved with a highly atroposelective electrophilic aromatic substitution catalyzed by a chiral‐at‐metal rhodium Lewis acid. Specifically, N‐arylpyrroles were alkylated with N‐acryloyl‐1H‐pyrazole electrophiles in up to 93 % yield and with up to >99.5 % ee, and follow‐up conversions reveal the synthetic utility of this new method. DFT calculations elucidate the origins of the observed excellent atroposelectivity. 相似文献
12.
Dr. Valentín Hornillos Dr. Manuel Pérez Dr. Martín Fañanás‐Mastral Prof. Dr. Ben L. Feringa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(17):5432-5441
An efficient and highly enantioselective copper‐catalyzed allylic alkylation of phosphonates and phosphine oxides with Grignard reagents and Taniaphos or phosphoramidites as chiral ligands is reported. Transformation of these products leads to a variety of new phosphorus‐containing chiral intermediates. 相似文献
13.
Summaryof main observation and conclusion It could be proposed that gold(I)-catalyzed reactions of ynamides with benzofurazan N-oxidesmightproceed through eitherO-attack or N-attack to affordα-oxo orα-imino Au(I)-carbenoidintermediates.Computational studies were performed to predict that benzofurazan N-oxides are ready to undergo the chemoselective N-attack tothe Au(I)-activatedynamides to generate theα-imino Au(I)-carbenoid intermediate.Experimental studies were carried out to confirm the computational results and the 7-nitroindole derivatives were synthesized in a concise and efficient manner.The unfavored O-attack for benzofurazan N-oxides,which is in contrast to nitrones and pyridine/quinoline N-oxides,in the Au(I)-catalyzed reactions with ynamides is rationalized. 相似文献
14.
Johanna Frey Alaleh Malekafzali Isabel Delso Sabine Choppin Franoise Colobert Joanna Wencel‐Delord 《Angewandte Chemie (International ed. in English)》2020,59(23):8844-8848
N?C axially chiral compounds have emerged recently as appealing motifs for drug design. However, the enantioselective synthesis of such molecules is still poorly developed and surprisingly no metal‐catalyzed atroposelective N‐arylations have been described. Herein, we disclose an unprecedented Cu‐catalyzed atroposelective N?C coupling that proceeds at room temperature. Such mild reaction conditions, which are a crucial parameter for atropostability of the newly generated products, are operative thanks to the use of hypervalent iodine reagents as a highly reactive coupling partners. A large panel of the N?C axially chiral compounds was afforded with very high enantioselectivity (up to >99 % ee) and good yields (up to 76 %). Post‐modifications of thus accessed atropisomeric compounds allows further expansion of the diversity of these appealing compounds. 相似文献
15.
Enantioselective Synthesis of Highly Functionalized Dihydrofurans through Copper‐Catalyzed Asymmetric Formal [3+2] Cycloaddition of β‐Ketoesters with Propargylic Esters 下载免费PDF全文
Fu‐Lin Zhu Ya‐Hui Wang De‐Yang Zhang Prof. Dr. Jie Xu Prof. Dr. Xiang‐Ping Hu 《Angewandte Chemie (International ed. in English)》2014,53(38):10223-10227
An enantioselective synthesis of highly functionalized dihydrofurans through a copper‐catalyzed asymmetric [3+2] cycloaddition of β‐ketoesters with propargylic esters has been developed. With a combination of Cu(OTf)2 and a chiral tridentate P,N,N ligand as the catalyst, a variety of 2,3‐dihydrofurans bearing an exocyclic double bond at the 2 position were obtained in good chemical yields and with good to high enantioselectivities. The exocyclic double bond can be hydrogenated in a highly diastereoselective fashion to give unusual cis‐2,3‐dihydrofuran derivatives, thus further enhancing the scope of this transformation. 相似文献
16.
Rahul K. Shukla Akshay M. Nair Salman Khan Chandra M. R. Volla 《Angewandte Chemie (International ed. in English)》2020,59(39):17042-17048
An efficient Cp*CoIII‐catalyzed C8‐dienylation of quinoline‐N‐oxides was achieved by employing allenes bearing leaving groups at the α‐position as the dienylating agents. The reaction proceeds by CoIII‐catalyzed C?H activation of quinoline‐N‐oxides and regioselective migratory insertion of the allene followed by a β‐oxy elimination, leading to overall dienylation. Site‐selective C?H activation was achieved with excellent selectivity under mild reaction conditions, and 30 mol % of a NaF additive was found to be crucial for the efficient dienylation. The methodology features high stereoselectivity, mild reaction conditions, and good functional‐group tolerance. C8‐alkenylation of quinoline‐N‐oxides was achieved in the case of allenes devoid of leaving groups as coupling partners. Furthermore, gram‐scale preparation and preliminary mechanistic experiments were carried out to gain insights into the reaction mechanism. 相似文献
17.
Copper‐Catalyzed Regioselective Cascade Alkylation and Cyclocondensation of Quinoline N‐Oxides with Diazo Esters: Direct Access to Conjugated π‐Systems 下载免费PDF全文
Aniruddha Biswas Ujjwal Karmakar Arun Pal Dr. Rajarshi Samanta 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(39):13826-13830
An inexpensive copper‐catalyzed cascade regioselective alkylation, followed by cyclocondensation of quinoline N‐oxides with α‐diazo esters has been achieved successfully to provide heteroarene‐containing conjugated π‐systems. The developed method is simple, straightforward, and economical with a broad range of substrate scope. The dual role of copper catalyst in the C?H bond functionalization and in Lewis acid‐promoted cyclization was explored. 相似文献
18.
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
19.
Wentao Wang Xiaohua Liu Dr. Weidi Cao Jun Wang Lili Lin Dr. Xiaoming Feng Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1664-1669
A highly enantioselective Friedel–Crafts (F–C) alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N′‐dioxide–Sc(OTf)3 complex has been developed that tolerates a wide range of substrates. The reaction proceeds in moderate to excellent yields and high enantioselectivities (85–92 % enantiomeric excess) using 2 mol % (for indole) or 0.5 mol % (for pyrrole) catalyst loading, which showed the potential value of the catalyst system. Meanwhile, a strong positive nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible working model is proposed to explain the origin of the activation and asymmetric induction. 相似文献
20.
Carina I. Jette Z. Jaron Tong Ryan G. Hadt Brian M. Stoltz 《Angewandte Chemie (International ed. in English)》2020,59(5):2033-2038
Herein, we report a Cu‐catalyzed enantioselective allylic alkylation using a γ‐butyrolactone‐derived silyl ketene acetal. Critical to the development of this work was the identification of a novel mono‐picolinamide ligand with the appropriate steric and electronic properties to afford the desired products in high yield (up to 96 %) and high ee (up to 95 %). Aryl, aliphatic, and unsubstituted allylic chlorides bearing a broad range of functionality are well‐tolerated. Spectroscopic studies reveal that a CuI species is likely the active catalyst, and DFT calculations suggest ligand sterics play an important role in determining Cu coordination and thus catalyst geometry. 相似文献