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1.
Yushuang Chen Yun Liu Zhaojing Li Prof. Dr. Shunxi Dong Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8129-8133
An enantioselective synthesis of α-aminoketone derivatives were readily available through a tandem insertion–[1,3] O-to-C rearrangement reaction. The rhodium salt and chiral N,N′-dioxide-indium(III) complex make up relay catalysis, which enables the O−H insertion of benzylic alcohols to N-sulfonyl-1,2,3-triazoles, and asymmetric [1,3]-rearrangement of amino enol ether intermediates, subsequently. Preliminary mechanistic studies suggested that the [1,3] O-to-C rearrangement step proceeded through an ion pair pathway. 相似文献
2.
Li Li Chenggang Mi Guanwang Huang Meirong Huang Yuyi Zhu Shao-Fei Ni Zhaofeng Wang Yong Huang 《Angewandte Chemie (International ed. in English)》2023,62(45):e202312793
Insertion reactions that involve stabilized electrophilic metallocarbenes are of great importance for installing α-heteroatoms to carbonyl compounds. Nevertheless, the limited availability of carbene precursors restricts the introduction of only a single heteroatom. In this report, we describe a new approach based on an I(III)/S(VI) reagent that promotes the cascade insertion of heteroatoms. This is achieved by sequentially generating two α-heteroatom-substituted metal carbenes in one reaction. We found that this mixed I(III)/S(VI) ylide reacts efficiently with a transition metal catalyst and an X−H bond (where X=O, N). This transformation leads to the sequential formation of a sulfoxonium- and an X-substituted Rh-carbenes, enabling further reactions with another Y−H bond. Remarkably, a wide range of symmetrical and unsymmetrical α,α-O,O-, α,α-O,N-, and α,α-N,N-subsituted ketones can be prepared under mild ambient conditions. In addition, we successfully demonstrated other cascades, such as CN/CN double amidation, C−H/C−S double insertion, and C−S/Y−H double insertion (where Y=S, N, O, C). Notably, the latter two cascades enabled the simultaneous installation of three functional groups to the α-carbon of carbonyl compounds in a single step. These reactions demonstrate the versatility of our approach, allowing for the synthesis of ketones and esters with multiple α-heteroatoms using a common precursor. 相似文献
3.
Qing-Xia Zhang Yao Li Jie Wang Chen Yang Cheng-Jun Liu Prof. Xin Li Prof. Jin-Pei Cheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(11):4580-4586
The enantioselective ketimine–ene reaction is one of the most challenging stereocontrolled reaction types in organic synthesis. In this work, catalytic enantioselective ketimine–ene reactions of 2-aryl-3H-indol-3-ones with α-methylstyrenes were achieved by utilizing a B(C6F5)3/chiral phosphoric acid (CPA) catalyst. These ketimine–ene reactions proceed well with low catalyst loading (B(C6F5)3/CPA=2 mol %/2 mol %) under mild conditions, providing rapid and facile access to a series of functionalized 2-allyl-indolin-3-ones with very good reactivity (up to 99 % yield) and excellent enantioselectivity (up to 99 % ee). Theoretical calculations reveal that enhancement of the acidity of the chiral phosphoric acid by B(C6F5)3 significantly reduces the activation free energy barrier. Furthermore, collective favorable hydrogen-bonding interactions, especially the enhanced N−H⋅⋅⋅O hydrogen-bonding interaction, differentiates the free energy of the transition states of CPA and B(C6F5)3/CPA, thereby inducing the improvement of stereoselectivity. 相似文献
4.
Guozhu Li Xiaoqiang Yan Jijun Jiang Hao Liang Chao Zhou Prof. Dr. Jun Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22622-22626
A new class of chiral cyclopentadienyl rhodium(I) complexes (CpRhI) bearing C2-symmetric chiral bridged-ring-fused Cp ligands was prepared. The complexes were successfully applied to the asymmetric C−H activation reaction of N-methoxybenzamides with quinones, affording a series of chiral hydrophenanthridinones in up to 82 % yield with up to 99 % ee. Interestingly, structure analysis reveals that the side wall of the optimal chiral CpRhI catalyst is vertically more extended, horizontally less extended, and closer to the metal center in comparison with the classic binaphthyl and spirobiindanyl CpRhI complexes, and may thus account for its superior catalytic performance. 相似文献
5.
Chiral Bis(imidazolidine)‐Derived NCN Pincer Rh Complex for Catalytic Asymmetric Mannich Reaction of Malononitrile with N‐Boc Imines 下载免费PDF全文
Prof. Dr. Takayoshi Arai Takuma Moribatake Prof. Dr. Hyuma Masu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10671-10675
Chiral bis(imidazolidine)‐derived NCN–rhodium complexes ([PhBidine‐RhX2] and [tBu‐PhBidine‐RhX2]) were prepared by a C?H insertion method, and the structures were unequivocally determined by X‐ray crystallographic analysis. The [tBu‐PhBidine‐Rh(OAc)2] complex smoothly catalyzed an asymmetric Mannich reaction of malononitrile with N‐Boc imines to give products in up to 94 % ee, which are useful for the synthesis of chiral α‐amino acids. 相似文献
6.
Guozhu Li Jijun Jiang Hui Xie Prof. Dr. Jun Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(18):4688-4694
The chiral transient directing group (TDG) strategy has been successfully introduced to the rhodium(III)-catalyzed asymmetric C−H activation. In the presence of a catalytic amount of a chiral amine and an achiral rhodium catalyst, various chiral phthalides were synthesized from simple aldehydes with high chemoselectivity, regioselectivity, and enantioselectivity (53 examples, up to 73 % yield and >99 % ee). It is noteworthy that the chiral induction model is different from the previously reported chiral TDG system using amino acid derivatives and palladium salts. The imino group generated in situ from chiral amine and aldehyde acts as the monodentate TDG to promote the C−H activation, stereoselectively generating the chiral rhodacycle bearing a chiral metal center. Moreover, the stereogenic center of the product is created and stereocontrolled during the Grignard-type addition of the C−Rh bond to aldehyde, rather than during the C−H activation step. 相似文献
7.
Bei-Bei Zhan Lei Wang Jun Luo Prof. Dr. Xu-Feng Lin Prof. Dr. Bing-Feng Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3596-3600
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
8.
Yushuang Chen Yun Liu Zhaojing Li Shunxi Dong Xiaohua Liu Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2020,59(21):8052-8056
An enantioselective synthesis of α‐aminoketone derivatives were readily available through a tandem insertion–[1,3] O‐to‐C rearrangement reaction. The rhodium salt and chiral N,N′‐dioxide‐indium(III) complex make up relay catalysis, which enables the O?H insertion of benzylic alcohols to N‐sulfonyl‐1,2,3‐triazoles, and asymmetric [1,3]‐rearrangement of amino enol ether intermediates, subsequently. Preliminary mechanistic studies suggested that the [1,3] O‐to‐C rearrangement step proceeded through an ion pair pathway. 相似文献
9.
A Powerful Chiral Phosphoric Acid Catalyst for Enantioselective Mukaiyama–Mannich Reactions 下载免费PDF全文
Dr. Fengtao Zhou Prof. Dr. Hisashi Yamamoto 《Angewandte Chemie (International ed. in English)》2016,55(31):8970-8974
A new BINOL‐derived chiral phosphoric acid bearing 2,4,6‐trimethyl‐3,5‐dinitrophenyl substituents at the 3,3′‐positions was developed. The utility of this chiral phosphoric acid is demonstrated by a highly enantioselective (ee up to >99 %) and diastereoselective (syn/anti up to >99:1) asymmetric Mukaiyama–Mannich reaction of imines with a wide range of ketene silyl acetals. Moreover, this method was successfully applied to the construction of vicinal tertiary and quaternary stereogenic centers with excellent diastereo‐ and enantioselectivity. Significantly, BINOL‐derived N‐triflyl phosphoramide constitutes a complementary catalyst system that allows the title reaction to be applied to more challenging imines without an N‐(2‐hydroxyphenyl) moiety. 相似文献
10.
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
11.
Dr. Jiaqiong Sun Weiliang Yuan Rong Tian Peiyuan Wang Dr. Xue-Peng Zhang Prof. Xingwei Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22895-22902
We report chiral RhIII cyclopentadienyl-catalyzed enantioselective synthesis of lactams and isochromenes through oxidative [4+1] and [5+1] annulation, respectively, between arenes and 1,3-enynes. The reaction proceeds through a C−H activation, alkenyl-to-allyl rearrangement, and a nucleophilic cyclization cascade. The mechanisms of the [4+1] annulations were elucidated by a combination of experimental and computational methods. DFT studies indicated that, following the C−H activation and alkyne insertion, a RhIII alkenyl intermediate undergoes δ-hydrogen elimination of the allylic C−H via a six-membered ring transition state to produce a RhIII enallene hydride intermediate. Subsequent hydride insertion and allyl rearrangement affords several rhodium(III) allyl intermediates, and a rare RhIII η4 ene-allyl species with π-agostic interaction undergoes SN2′-type external attack by the nitrogen nucleophile, instead of C−N reductive elimination, as the stereodetermining step. 相似文献
12.
Dr. Lucie Jarrige Prof. Vincent Gandon Dr. Géraldine Masson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(6):1406-1413
A stable asymmetric intramolecular Povarov reaction has been established to provide an efficient method to access structurally diverse trans,trans-trisubstituted tetrahydrochromeno[4,3-b]quinolines in high stereoselectivities of up to >99:1 diastereomeric ratio and 99 % enantiomeric excess, without any purification step. Additionally, to facilitate large-scale application of this method, a low catalyst loading protocol was employed, 0.2 mol % chiral phosphoric acid, which provided the cycloadducts without any loss in yield and enantioselectivity. Theoretical studies revealed that the reaction occurred through a sequential Mannich reaction and an intramolecular Friedel–Crafts reaction, wherein the phosphoric acid acted as a bifunctional catalyst to activate the para-phenolic dienophile and N-2-hydroxy-2-azadiene simultaneously. 相似文献
13.
[RhIII(Cp*)]‐Catalyzed ortho‐Selective Direct C(sp2)H Bond Amidation/Amination of Benzoic Acids by N‐Chlorocarbamates and N‐Chloromorpholines. A Versatile Synthesis of Functionalized Anthranilic Acids 下载免费PDF全文
Fo‐Ning Ng Prof. Dr. Zhongyuan Zhou Prof. Dr. Wing‐Yiu Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(15):4474-4480
A RhIII‐catalyzed direct ortho‐C?H amidation/amination of benzoic acids with N‐chlorocarbamates/N‐chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent ortho‐selectivity and functional‐group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO2Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N‐chlorocarbamate afforded an amido–rhodium(III) complex, which was isolated and structurally characterized by X‐ray crystallography. This finding confirmed that the C?N bond formation results from the cross‐coupling of N‐chlorocarbamate with the aryl–rhodium(III) complex. Yet, the mechanistic details regarding the C?N bond formation remain unclear; pathways involving 1,2‐aryl migration and rhodium(V)– nitrene are plausible. 相似文献
14.
Ryo Yoshimura Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(22):4969-4973
It has been established that an unsubstituted cyclopentadienyl rhodium(III) (CpRhIII) complex is a highly active catalyst for the aerobic oxidative ortho C−H bond olefination of sterically demanding ortho-substituted benzamides with alkenes. This catalysis was successfully applied to the diastereoselective synthesis of axially chiral N,N-dialkylbenzamides. The combination of the ruthenium(II)-catalyzed enantioselective hydrogenation and the CpRhIII-catalyzed diastereoselective ortho C−H bond olefination enabled the asymmetric synthesis of axially chiral N,N-dialkylbenzamide derivatives with high ee values. 相似文献
15.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(50):16112-16116
An asymmetric copper‐catalyzed alkylation of quinoline N ‐oxides with chiral Cu–alkyl species, generated by migratory insertion of a vinylarene into a chiral Cu−H complex, is reported. A variety of quinoline N ‐oxides and vinylarenes underwent this Cu‐catalyzed enantioselective alkylation reaction, affording the corresponding chiral alkylated N‐heteroarenes in high yield with high‐to‐excellent enantioselectivity. This enantioselective protocol represents the first general and practical approach to access a wide range of chiral alkylated quinolines. 相似文献
16.
Enantioselective NH Insertion Reaction of α‐Aryl α‐Diazoketones: An Efficient Route to Chiral α‐Aminoketones 下载免费PDF全文
Bin Xu Prof. Shou‐Fei Zhu Xiao‐Dong Zuo Zhi‐Chao Zhang Prof. Qi‐Lin Zhou 《Angewandte Chemie (International ed. in English)》2014,53(15):3913-3916
A highly enantioselective N? H insertion reaction of α‐diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α‐aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. 相似文献
17.
Rhodium‐Catalyzed Regioselective N2‐Alkylation of Benzotriazoles with Diazo Compounds/Enynones via a Nonclassical Pathway 下载免费PDF全文
Kai Wang Ping Chen Danqing Ji Prof. Dr. Xinhao Zhang Guangyang Xu Prof. Dr. Jiangtao Sun 《Angewandte Chemie (International ed. in English)》2018,57(38):12489-12493
A novel rhodium‐catalyzed highly selective N2‐alkylation of benzotriazoles with diazo compounds/enynones is achieved, providing N2‐alkylated benzotriazoles in good to excellent yields and with excellent N2 selectivities. Importantly, different to traditional carbene insertion into X?H (X=N, O etc) bonds, DFT calculations disclose that this selective N2‐alkylation probably proceeds through a formal 1,3‐ rather than 1,2‐H shift to give the final products. 相似文献
18.
Bin Xu Shou‐Fei Zhu Xiao‐Dong Zuo Zhi‐Chao Zhang Qi‐Lin Zhou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(15):3994-3997
A highly enantioselective N H insertion reaction of α‐diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α‐aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. 相似文献
19.
Qing‐Xia Zhang Yao Li Jie Wang Chen Yang Cheng‐Jun Liu Xin Li Jin‐Pei Cheng 《Angewandte Chemie (International ed. in English)》2020,59(11):4550-4556
The enantioselective ketimine–ene reaction is one of the most challenging stereocontrolled reaction types in organic synthesis. In this work, catalytic enantioselective ketimine–ene reactions of 2‐aryl‐3H‐indol‐3‐ones with α‐methylstyrenes were achieved by utilizing a B(C6F5)3/chiral phosphoric acid (CPA) catalyst. These ketimine–ene reactions proceed well with low catalyst loading (B(C6F5)3/CPA=2 mol %/2 mol %) under mild conditions, providing rapid and facile access to a series of functionalized 2‐allyl‐indolin‐3‐ones with very good reactivity (up to 99 % yield) and excellent enantioselectivity (up to 99 % ee). Theoretical calculations reveal that enhancement of the acidity of the chiral phosphoric acid by B(C6F5)3 significantly reduces the activation free energy barrier. Furthermore, collective favorable hydrogen‐bonding interactions, especially the enhanced N?H???O hydrogen‐bonding interaction, differentiates the free energy of the transition states of CPA and B(C6F5)3/CPA, thereby inducing the improvement of stereoselectivity. 相似文献
20.
Jun-Yan Wu Zhen Li Dr. Jin-Dong Yang Prof. Dr. Jin-Pei Cheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23990-23998
Thermodynamic knowledge of the metal–ligand (M−L) σ-bond strength is crucial to understanding metal-mediated transformations. Here, we developed a method for determining the Pd−X (X=OR and NHAr) bond heterolysis energies (ΔGhet(Pd−X)) in DMSO taking [(tmeda)PdArX] (tmeda=N,N,N′,N′-tetramethylethylenediamine) as the model complexes. The ΔGhet(Pd−X) scales span a range of 2.6–9.0 kcal mol−1 for ΔGhet(Pd−O) values and of 14.5–19.5 kcal mol−1 for ΔGhet(Pd−N) values, respectively, implying a facile heterolytic detachment of the Pd ligands. Structure-reactivity analyses of a modeling Pd-mediated X−H bond activation reveal that the M−X bond metathesis is dominated by differences of the X−H and Pd−X bond strengths, the former being more influential. The ΔGhet(Pd−X) and pKa(X−H) parameters enable regulation of reaction thermodynamics and chemoselectivity and diagnosing the probability of aniline activation with Pd−X complexes. 相似文献