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1.
Construction of a Chiral Silicon Center by Rhodium‐Catalyzed Enantioselective Intramolecular Hydrosilylation 下载免费PDF全文
Dr. Yuki Naganawa Tomoya Namba Mayu Kawagishi Prof. Dr. Hisao Nishiyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9319-9322
Rhodium‐catalyzed enantioselective desymmetrizing intramolecular hydrosilylation of symmetrically disubstituted hydrosilanes is described. The original axially chiral phenanthroline ligand (S)‐BinThro (Binol‐derived phenanthroline) was found to work as an effective chiral catalyst for this transformation. A chiral silicon stereogenic center is one of the chiral motifs gaining much attention in asymmetric syntheses and the present protocol provides cyclic five‐membered organosilanes incorporating chiral silicon centers with high enantioselectivities (up to 91 % ee). The putative active RhI catalyst takes the form of an N,N,O‐tridentate coordination complex, as determined by several complementary experiments. 相似文献
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Asymmetric Induction at Remote Quaternary Centers of Cyclohexadienones by Rhodium‐Catalyzed Conjugate Hydrosilylation 下载免费PDF全文
Dr. Yuki Naganawa Mayu Kawagishi Dr. Jun‐ichi Ito Prof. Dr. Hisao Nishiyama 《Angewandte Chemie (International ed. in English)》2016,55(24):6873-6876
The enantioselective desymmetrizing conjugate hydrosilylation of prochiral differently γ,γ‐disubstituted cyclohexadienone derivatives 2 to furnish the corresponding cyclohexenones 4 with a remote chiral all‐carbon quaternary center at the γ position is described. Chiral rhodium–bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with high enantiomeric ratios. 相似文献
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Justin S. Marcum Tiffany R. Taylor Simon J. Meek 《Angewandte Chemie (International ed. in English)》2020,59(33):14070-14075
A catalytic method for the site‐selective and enantioselective synthesis of functionalized arenes by the intermolecular hydroarylation of terminal and internal 1,3‐dienes with aryl pinacolato boronates is reported. The reactions are promoted by 5.0 mol % of a readily available monodentate phosphoramidite‐Ni complex in ethanol, affording a variety of enantioenriched products in up to 96 % yield and 99:1 er. Mechanistic studies indicate that Ni–allyl formation is irreversible and related to the nature of the arylboronate. 相似文献
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Rhodium‐Catalyzed Intramolecular Hydroarylation of 1‐Halo‐1‐alkynes: Regioselective Synthesis of Semihydrogenated Aromatic Heterocycles 下载免费PDF全文
Hirohiko Murase Kousuke Senda Masato Senoo Prof. Dr. Takeshi Hata Prof. Dr. Hirokazu Urabe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(1):317-322
The regioselective intramolecular hydroarylation of (3‐halo‐2‐propynyl)anilines, (3‐halo‐2‐propynyl) aryl ethers, or (4‐halo‐3‐butynyl) aryl ethers was efficiently catalyzed by Rh2(OCOCF3)4 to give semihydrogenated aromatic heterocycles, such as 4‐halo‐1,2‐dihydroquinolines, 4‐halo‐3‐chromenes, or 4‐(halomethylene)chromans, in good to excellent yields. Some synthetic applications taking advantage of the halo‐substituents of the products are also illustrated. 相似文献
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Stephanie Ganss Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2016,55(33):9738-9742
A highly attractive route toward macrolactones, which form the cyclic scaffold of a multitude of diverse natural compounds, is described. Although many chemical approaches to this structural motif have been explored, an asymmetric variant of the cyclization is unprecedented. Herein we present an enantioselective macrolactonization through an intramolecular atom‐economical rhodium‐catalyzed coupling of ω‐allenyl‐substituted carboxylic acids. The use of a modified diop ligand, chiral DTBM‐diop, led to high enantioselectivity (up to 93 % ee). The reaction tolerated a large variety of functionalities, including α,β‐unsaturated carboxylic acids and depsipeptides, and provided the desired macrocycles with very high enantio‐ and diastereoselectivity. 相似文献
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Yuli He Chuang Liu Prof. Lei Yu Prof. Shaolin Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(48):21714-21718
A highly enantio- and regioselective hydroarylation process of vinylarenes with aryl halides has been developed using a NiH catalyst and a new chiral bis imidazoline ligand. A broad range of structurally diverse, enantioenriched 1,1-diarylalkanes, a structure found in a number of biologically active molecules, have been obtained with excellent yields and enantioselectivities under extremely mild conditions. 相似文献
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Pierre‐Alain R. Breuil Frederic W. Patureau Joost N. H. Reek Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(12):2162-2165
H bonds make the catalysts! A single hydrogen bond between ligands coordinated to a rhodium center is critical for the formation of pure supramolecular catalysts for asymmetric hydrogenation reactions. The ester group of the amidite ligand (see scheme) also forms a hydrogen bond with the coordinated substrate. Use of the heterocomplex afforded the highest enantioselectivity reported to date for the hydrogenation of several ester substrates.
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Highly Enantioselective Rhodium‐Catalyzed Addition of Arylboroxines to Simple Aryl Ketones: Efficient Synthesis of Escitalopram 下载免费PDF全文
Linwei Huang Jinbin Zhu Guangjun Jiao Dr. Zheng Wang Prof. Dr. Xingxin Yu Prof. Dr. Wei‐Ping Deng Prof. Dr. Wenjun Tang 《Angewandte Chemie (International ed. in English)》2016,55(14):4527-4531
Highly enantioselective additions of arylboroxines to simple aryl ketones have been achieved for the first time with a Rh/(R,R,R,R)‐WingPhos catalyst, thus providing a range of chiral diaryl alkyl carbinols with excellent ee values and yields. (R,R,R,R)‐WingPhos has been proven to be crucial for the high reactivity and enantioselectivity. The method has enabled a new, concise, and enantioselective synthesis of the antidepressant drug escitalopram. 相似文献
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Rhodium‐Catalyzed Stereoselective Amination of Thioethers with N‐Mesyloxycarbamates: DMAP and Bis(DMAP)CH2Cl2 as Key Additives 下载免费PDF全文
Prof. Dr. Hélène Lebel Henri Piras Johan Bartholoméüs 《Angewandte Chemie (International ed. in English)》2014,53(28):7300-7304
A stereoselective Rh‐catalyzed intermolecular amination of thioethers using a readily available chiral N‐mesyloxycarbamate to produce sulfilimines in excellent yields and diastereomeric ratio is described. A catalytic mixture of 4‐dimethylaminopyridine (DMAP) and bis(DMAP)CH2Cl2 proved pivotal in achieving high selectivity. The X‐ray crystal structure of the (DMAP)2?[Rh2{(S)‐nttl}4] complex was obtained and mechanistic studies suggested a RhII‐RhIII complex as the catalytically active species. 相似文献
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Ting Liu Yunhui Yang Congyang Wang 《Angewandte Chemie (International ed. in English)》2020,59(34):14256-14260
Transition‐metal‐catalyzed hydroarylation of unactivated alkenes with strategic use of remote coordinating functional groups has received significant attention recently to address the issues of both low reactivity and poor selectivity. The bidentate 8‐aminoquinoline amide group is the most successfully adopted in unactivated alkenes for Pd and Ni catalysis. We describe the first manganese‐catalyzed hydroarylation of unactivated alkenes bearing diverse simple functionalities with arylboronic acids. A series of δ‐ and γ‐arylated amides, ketones, pyridines, and amines was accessed with excellent regioselectivity and in high yields. Hydroalkenylation of unactivated alkenes was also shown to be applicable under this manganese‐catalysis regime. The method features earth‐abundant manganese catalysis, easily available substrates, broad functional‐group tolerance, and excellent regioselective control. 相似文献
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Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution 下载免费PDF全文
Adrian B. Pritzius Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2015,54(52):15818-15822
A Z‐selective rhodium‐catalyzed hydrothiolation of 1,3‐disubstituted allenes and subsequent oxidation towards the corresponding allylic sulfones is described. Using the bidentate 1,4‐bis(diphenylphosphino)butane (dppb) ligand, Z/E‐selectivities up to >99:1 were obtained. The highly atom‐economic desymmetrization reaction tolerates functionalized aromatic and aliphatic thiols. Additionally, a variety of symmetric internal allenes, as well as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities. Starting from chiral but racemic 1,3‐disubstituted allenes a dynamic kinetic resolution (DKR) could be achieved by applying (S,S)‐Me‐DuPhos as the chiral ligand. The desired Z‐allylic sulfones were obtained in high yields and enantioselectivities up to 96 % ee. 相似文献
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Ying Cheng Dr. Wanrong Dong Han Wang Prof. Dr. Carsten Bolm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10821-10824
Rhodium‐catalyzed ortho‐amidations of sulfoximines lead to key intermediates for the preparation of thiadiazine 1‐oxides. Following a straightforward protocol, a variety of synthetically valuable compounds can be obtained, thus circumventing common multistep approaches towards potentially bioactive products. 相似文献
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