共查询到20条相似文献,搜索用时 15 毫秒
1.
Gaoyuan Ma Dr. Jun Deng Prof. Dr. Mukund P. Sibi 《Angewandte Chemie (International ed. in English)》2014,53(44):11818-11821
Can organocatalysts that incorporate fluxional groups provide enhanced selectivity in asymmetric transformations? To address this issue, we have designed chiral 4‐dimethylaminopyridine (DMAP) catalysts with fluxional chirality. These catalysts were found to be efficient in promoting the acylative kinetic resolution of secondary alcohols and axially chiral biaryl compounds with selectivity factors of up to 37 and 51, respectively. 相似文献
2.
Gaoyuan Ma Prof. Dr. Mukund P. Sibi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11644-11657
Biaryl compounds with axial chirality are very common in synthetic chemistry, especially in catalysis. Axially chiral biaryls are important due to their biological activities and extensive applications in asymmetric catalysis. Thus the development of efficient enantioselective methods for their synthesis has attracted considerable attention. This Minireview discusses the progress made in catalytic kinetic resolution of biaryl compounds and chronicles significant advances made recently in catalytic kinetic resolution of biaryl scaffolds. 相似文献
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Ye‐Hui Chen Heng‐Hui Li Xiao Zhang Shao‐Hua Xiang Shaoyu Li Bin Tan 《Angewandte Chemie (International ed. in English)》2020,59(28):11374-11378
Presented here is a class of novel axially chiral aryl‐p‐quinones as platform molecules for the preparation of non‐C2 symmetric biaryldiols. Two sets of aryl‐p‐quinone frameworks were synthesized with remarkable enantiocontrol by means of chiral phosphoric acid catalyzed enantioselective arylation of p‐quinones by central‐to‐axial chirality conversion. These aryl‐p‐quinones were then used to access a wide spectrum of highly functionalized non‐C2 symmetric biaryldiols with excellent retention of the enantiopurity. 相似文献
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Practical Organocatalytic Synthesis of Functionalized Non‐C2‐Symmetrical Atropisomeric Biaryls 下载免费PDF全文
Dr. Hongyin Gao Prof. Dr. Qing‐Long Xu Craig Keene Dr. Muhammed Yousufuddin Prof. Dr. Daniel H. Ess Prof. Dr. László Kürti 《Angewandte Chemie (International ed. in English)》2016,55(2):566-571
An organic acid catalyzed direct arylation of aromatic C(sp2)? H bonds in phenols and naphthols for the preparation of 1,1′‐linked functionalized biaryls was developed. The products are non‐C2‐symmetrical, atropoisomeric, and represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, is readily scaled up (up to 98 mmol), and the structurally diverse 2,2′‐dihydroxy biaryl (i.e., BINOL‐type), as well as 2‐amino‐2′‐hydroxy products (i.e., NOBIN‐type) are formed with complete regioselectivity. Density‐functional calculations suggest that the quinone and imino‐quinone monoacetal coupling partners are exclusively arylated at their α‐position by an asynchronous [3,3]‐sigmatropic rearrangement of a mixed acetal species which is formed in situ under the reaction conditions. 相似文献
6.
Enantiodivergent Atroposelective Synthesis of Chiral Biaryls by Asymmetric Transfer Hydrogenation: Chiral Phosphoric Acid Catalyzed Dynamic Kinetic Resolution 下载免费PDF全文
Prof. Dr. Keiji Mori Tsubasa Itakura Prof. Dr. Takahiko Akiyama 《Angewandte Chemie (International ed. in English)》2016,55(38):11642-11646
Reported herein is an enantiodivergent synthesis of chiral biaryls by a chiral phosphoric acid catalyzed asymmetric transfer hydrogenation reaction. Upon treatment of biaryl lactols with aromatic amines and a Hantzsch ester in the presence of chiral phosphoric acid, dynamic kinetic resolution (DKR) involving a reductive amination reaction proceeded smoothly to furnish both R and S isomers of chiral biaryls with excellent enantioselectivities by proper choice of hydroxyaniline derivative. This trend was observed in wide variety of substrates, and various chiral biphenyl and phenyl naphthyl adducts were synthesized with satisfactory enantioselectivities in enantiodivergent fashion. The enantiodivergent synthesis of synthetically challenging, chiral o‐tetrasubstituted biaryls were also accomplished, and suggests high synthetic potential of the present method. 相似文献
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Elizabeth S. Munday Markas A. Grove Taisiia Feoktistova Alexander C. Brueckner Daniel M. Walden Claire M. Young Alexandra M. Z. Slawin Andrew D. Campbell Paul Ha‐Yeon Cheong Andrew D. Smith 《Angewandte Chemie (International ed. in English)》2020,59(20):7897-7905
Axially chiral phenols are attractive targets in organic synthesis. This motif is central to many natural products and widely used as precursors to, or directly, as chiral ligands and catalysts. Despite their utility few simple catalytic methods are available for their synthesis in high enantiopurity. Herein the atropselective acylation of a range of symmetric biaryl diols is investigated using isothiourea catalysis. Studies on a model biaryl diol substrate shows that the high product er observed in the process is a result of two successive enantioselective reactions consisting of an initial enantioselective desymmetrization coupled with a second chiroablative kinetic resolution. Extension of this process to a range of substrates, including a challenging tetraorthosubstituted biaryl diol, led to highly enantioenriched products (14 examples, up to 98:2 er), with either HyperBTM or BTM identified as the optimal catalyst depending upon the substitution pattern within the substrate. Computation has been used to understand the factors that lead to high enantiocontrol in this process, with maintenance of planarity to maximize a 1,5‐S???O interaction within the key acyl ammonium intermediate identified as the major feature that determines atropselective acylation and thus product enantioselectivity. 相似文献
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Ye-Hui Chen Heng-Hui Li Xiao Zhang Shao-Hua Xiang Shaoyu Li Prof. Dr. Bin Tan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11470-11474
Presented here is a class of novel axially chiral aryl-p-quinones as platform molecules for the preparation of non-C2 symmetric biaryldiols. Two sets of aryl-p-quinone frameworks were synthesized with remarkable enantiocontrol by means of chiral phosphoric acid catalyzed enantioselective arylation of p-quinones by central-to-axial chirality conversion. These aryl-p-quinones were then used to access a wide spectrum of highly functionalized non-C2 symmetric biaryldiols with excellent retention of the enantiopurity. 相似文献
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Dr. Changgui Zhao Fangyi Li Prof. Dr. Jian Wang 《Angewandte Chemie (International ed. in English)》2016,55(5):1820-1824
The dynamic kinetic resolution of 6‐hydroxypyranones with enals or alkynals through an asymmetric redox esterification is catalyzed by a chiral N‐heterocyclic carbene. The resulting esters are obtained in good to high yields and with high levels of enantio‐ and diastereocontrol. The reaction products are further derivatized to obtain functionalized sugar derivatives and natural products. 相似文献
12.
Intermolecular Dynamic Kinetic Resolution Cooperatively Catalyzed by an N‐Heterocyclic Carbene and a Lewis Acid 下载免费PDF全文
Zijun Wu Fangyi Li Prof. Dr. Jian Wang 《Angewandte Chemie (International ed. in English)》2015,54(5):1629-1633
The ubiquitous structure of δ‐lactones makes the development of new methods for their enantioselective and stereoselective synthesis an important ongoing challenge. The intermolecular dynamic kinetic resolution (DKR) of β‐halo‐α‐ketoesters cooperatively catalyzed by an N‐heterocyclic carbene and a Lewis acid generates two contiguous stereocenters with remarkable diastereoselectivity through an oxidation/lactonization sequence. 相似文献
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Dipl.‐Chem. Patrick Bongen Prof. Dr. Jörg Pietruszka Dr. Robert Christian Simon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(35):11063-11070
An efficient asymmetric synthesis of (S)‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 8 a ) and (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 8 b ) was established. Key to the success was the highly stereoselective enzymatic kinetic resolution of the corresponding methyl or ethyl esters that was further developed into a dynamic process. As a reliable and fast tool for analysing the enantiomeric excess, HPLC coupled with a CD detector was utilized. The route was completed by a Friedel–Crafts acylation of ethyl (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylate ( 7 c ) followed by saponification leading to (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 2 ), an analgesic agent. 相似文献
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Yingguo Liu Pankaj Kumar Majhi Runjiang Song Chengli Mou Lin Hao Huifang Chai Zhichao Jin Yonggui Robin Chi 《Angewandte Chemie (International ed. in English)》2020,59(10):3859-3863
A catalytic dynamic kinetic resolution and asymmetric acylation reaction of hydroxyphthalides is developed. The reaction involves formation of a carbene catalyst derived chiral acyl azolium intermediate that effectively differentiates the two enantiomers of racemic hydroxyphthalides. The method allows quick access to enantiomerically enriched phthalidyl esters with proven applications in medicine. It also enables asymmetric modification of natural products and other functional molecules that contain acetal/ketal groups, such as corollosporine and fimbricalyxlactone C. 相似文献
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Kosaku Horiguchi Eri Yamamoto Dr. Kodai Saito Prof. Dr. Masahiro Yamanaka Prof. Dr. Takahiko Akiyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8078-8083
Asymmetric synthesis of tetrahydrobenzodiazepines was achieved by transfer hydrogenation of dihydrobenzodiazepines with benzothiazoline having a hydrogen‐bonding donor substituent by means of a newly synthesized chiral phosphoric acid. This method was applicable to various racemic dihydrobenzodiazepines to give the corresponding products in good yields with excellent diastereoselectivities and enantioselectivities taking advantage of the dynamic kinetic resolution. Furthermore, the effect of bulky substituent at 3,3′‐position on the catalyst and hydrogen‐bonding donor substituent on benzothiazoline was fully elucidated by the theoretical study. 相似文献
16.
Catalytic Enantioselective Synthesis of Atropisomeric Biaryls: A Cation‐Directed Nucleophilic Aromatic Substitution Reaction 下载免费PDF全文
Roly J. Armstrong Prof. Dr. Martin D. Smith 《Angewandte Chemie (International ed. in English)》2014,53(47):12822-12826
A catalytic enantioselective nucleophilic aromatic substitution reaction which yields axially chiral biaryl derivatives in excellent yields with e.r. values of up to 97:3 has been developed. This process uses a chiral counterion to direct the addition of thiophenolate to a prochiral dichloropyrimidine by a tandem desymmetrization/kinetic resolution mechanism. The products can be derivatized to a range of atropisomeric structures without any reduction in enantioenrichment, thus offering access to unexplored chiral biaryl architectures. 相似文献
17.
Subramani Rajkumar Mengyao Tang Xiaoyu Yang 《Angewandte Chemie (International ed. in English)》2020,59(6):2333-2337
An efficient method for the asymmetric synthesis of 4H‐3,1‐benzoxazines was developed by kinetic resolution of 2‐amido benzyl alcohols using chiral phosphoric acid catalyzed intramolecular cyclizations. A broad range of benzyl alcohols (both secondary and tertiary alcohols) were kinetically resolved with high selectivities, with an s factor of up to 94. Mechanistic studies were performed to elucidate the mechanism of these reactions, wherein the amide moieties reacted as the electrophiles. Gram‐scale reaction and facile transformations of the chiral products demonstrate the potential of this method in asymmetric synthesis of biologically active chiral heterocycles. 相似文献
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Atropoenantioselective Redox‐Neutral Amination of Biaryl Compounds through Borrowing Hydrogen and Dynamic Kinetic Resolution 下载免费PDF全文
Dr. Jianwei Zhang Prof. Dr. Jian Wang 《Angewandte Chemie (International ed. in English)》2018,57(2):465-469
We report herein a novel atropoenantioselective redox‐neutral amination of biaryl compounds triggered by a cascade of borrowing hydrogen and dynamic kinetic resolution under the cooperative catalysis of a chiral iridium complex and an achiral Brønsted acid. This protocol features broad substrate scope and good functional‐group tolerance, and allows the rapid assembly of axially chiral biaryl compounds in good to high yields and with high to excellent enantioselectivity. 相似文献
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Scalable Synthesis of the Potent HIV Inhibitor BMS‐986001 by Non‐Enzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT) 下载免费PDF全文
Dr. Adrian Ortiz Dr. Tamas Benkovics Dr. Gregory L. Beutner Dr. Zhongping Shi Dr. Michael Bultman Dr. Jeffrey Nye Dr. Chris Sfouggatakis Dr. David R. Kronenthal 《Angewandte Chemie (International ed. in English)》2015,54(24):7185-7188
Described herein is the synthesis of BMS‐986001 by employing two novel organocatalytic transformations: 1) a highly selective pyranose to furanose ring tautomerization to access an advanced intermediate, and 2) an unprecedented small‐molecule‐mediated dynamic kinetic resolution to access a variety of enantiopure pyranones, one of which served as a versatile building block for the multigram, stereoselective, and chromatography‐free synthesis of BMS‐986001. The synthesis required five chemical transformations and resulted in a 44 % overall yield. 相似文献
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A Practical Aryl Unit for Azlactone Dynamic Kinetic Resolution: Orthogonally Protected Products and A Ligation‐Inspired Coupling Process 下载免费PDF全文
Dr. Sean Tallon Dr. Francesco Manoni Prof. Stephen J. Connon 《Angewandte Chemie (International ed. in English)》2015,54(3):813-817
The first strategy for bringing about enantioselective azlactone dynamic kinetic resolution to generate orthogonally protected amino acids has been developed. In the presence of a C2‐symmetric squaramide‐based catalyst, benzyl alcohol reacts with novel yet readily prepared tetrachloroisopropoxycarbonyl‐substituted azlactones to generate trapped phthalimide products of significant synthetic interest with excellent enantiocontrol. These materials are masked amino acids which are demonstrably orthogonally protected: cleavage of the phthalimide can be achieved in the presence of the ester and vice versa. This process could be utilized to bring about a highly stereoselective ligation‐type coupling of protected serines (at stoichiometric loadings) with racemic azlactones derived from both natural and abiotic amino acids. After deprotection, a subsequent base‐mediated O→N acyl transfer occurs to form a dipeptide. 相似文献