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Over the past two decades, significant advances have been made towards developing chemically catalyzed asymmetric cyanohydrin syntheses. Preparations that were classically highly substrate specific, often using stoichiometric quantities of reagents, have been revolutionized by a new generation of catalysts. Methods currently available rival, and in many cases surpass, enzymatic procedures in terms of synthetic utility, generic applicability, and enantioselectivity. Such protocols are increasingly finding application in the syntheses of both biologically active natural products and therapeutically important synthetic compounds. 相似文献
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Shutao Sun Yingang Ma Ziqiang Liu Lei Liu 《Angewandte Chemie (International ed. in English)》2021,60(1):176-180
A manganese‐catalyzed oxidative kinetic resolution of cyclic benzylic ethers through asymmetric C(sp3)?H oxidation is reported. The practical approach is applicable to a wide range of 1,3‐dihydroisobenzofurans bearing diverse functional groups and substituent patterns at the α position with extremely efficient enantiodiscrimination. The generality of the strategy was further demonstrated by efficient oxidative kinetic resolution of another type of five‐membered cyclic benzylic ether, 2,3‐dihydrobenzofurans, and six‐membered 6H‐benzo[c]chromenes. Direct late‐stage oxidative kinetic resolution of bioactive molecules that are otherwise difficult to access was further explored. 相似文献
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Cooperative Catalysis: Enantioselective Propargylic Alkylation of Propargylic Alcohols with Enecarbamates Using Ruthenium/Phosphoramide Hybrid Catalysts 下载免费PDF全文
Yasushi Senda Dr. Kazunari Nakajima Prof. Dr. Yoshiaki Nishibayashi 《Angewandte Chemie (International ed. in English)》2015,54(13):4060-4064
The diastereo‐ and enantioselective propargylic alkylation of propargylic alcohols with E‐enecarbamates in the presence of a catalytic amount of thiolate‐bridged diruthenium complexes bearing an optically active phosphoramide moiety gives the corresponding propargylic alkylated products (up to 97 % ee). 相似文献
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Stereoselective Organocatalytic Synthesis of Oxindoles with Adjacent Tetrasubstituted Stereocenters 下载免费PDF全文
Oliver D. Engl Dr. Sven P. Fritz Prof. Dr. Helma Wennemers 《Angewandte Chemie (International ed. in English)》2015,54(28):8193-8197
Oxindoles with adjacent tetrasubstituted stereocenters were obtained in high yields and stereoselectivities by organocatalyzed conjugate addition reactions of monothiomalonates (MTMs) to isatin‐derived N‐Cbz ketimines. The method requires only a low catalyst loading (2 mol %) and proceeds under mild reaction conditions. Both enantiomers are accessible in good yields and excellent stereoselectivities by using either Takemoto’s catalyst or a cinchona alkaloid derivative. The synthetic methodology allowed establishment of a straightforward route to derivatives of the gastrin/cholecystokinin‐B receptor antagonist AG‐041R. 相似文献
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Chiral Phosphoric Acid Catalyzed Kinetic Resolution of Indolines Based on a Self‐Redox Reaction 下载免费PDF全文
Dr. Kodai Saito Prof. Dr. Takahiko Akiyama 《Angewandte Chemie (International ed. in English)》2016,55(9):3148-3152
A strategy for oxidative kinetic resolution of racemic indolines was developed, employing salicylaldehyde derivative as the pre‐resolving reagent and chiral phosphoric acid as the catalyst. The iminium intermediate, formed by the condensation reaction of an enantiomer of indoline with salicylaldehyde derivative, was hydrogenated by the same enantiomer of indoline to afford another enantiomer of indoline by a self‐redox mechanism. The oxidative kinetic resolution of 2‐aryl‐substituted indolines proceeded to give enantiomers in good yields with excellent enantioselectivities. 相似文献
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Magnesium Complexes as Highly Effective Catalysts for Conjugate Cyanation of α,β‐Unsaturated Amides and Ketones 下载免费PDF全文
Jinlong Zhang Xihong Liu Prof. Rui Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4911-4915
Asymmetric cyanation of trimethylsilyl cyanide (TMSCN) with α,β‐unsaturated amides and ketones, respectively, catalyzed by bifunctional mononuclear 1,1′‐bi‐2‐naphthol (BINOL)–Mg and binuclear bis(prophenol)–Mg catalysts was realized. A series of synthetically important 1,4‐cyano products were obtained with good to high enantioselectivities (up to 97 % ee). 相似文献
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Prof. Kazutaka Shibatomi 《Chemical record (New York, N.Y.)》2023,23(7):e202300061
This account summarizes our recent efforts in the enantioselective organocatalytic synthesis of chiral halogenated compounds. The enantioselective α-halogenation of aldehydes, decarboxylative chlorination of β-keto acids, and enantioselective C−C bond formation at the trifluoromethylated prochiral carbon to yield the corresponding organohalides with chlorinated, fluorinated, or trifluoromethylated chiral stereogenic centers are discussed. We applied common organocatalysts, such as Jørgensen-Hayashi catalyst and cinchona alkaloid-derivatived catalyst, and developed novel chiral amine catalysts for these reactions. This account also discusses stereospecific derivatizations of the resulting chiral halogenated compounds via nucleophilic substitution. Thus, we synthesized many novel chiral compounds that have not been reported, even as racemates. 相似文献
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Organocatalytic Enantioselective Cross‐Vinylogous Rauhut–Currier Reaction of Methyl Coumalate with Enals 下载免费PDF全文
Qiwen Liu Prof. Dr. Liansuo Zu 《Angewandte Chemie (International ed. in English)》2018,57(30):9505-9509
The organocatalytic enantioselective intermolecular cross‐vinylogous Rauhut–Currier (RC) reaction of methyl coumalate with α,β‐unsaturated aldehydes is reported, and the enals are activated by iminium catalysis to serve as the Michael acceptors and methyl coumalate is used as an activated diene to generate a latent enolate. The excellent selectivity is driven by the aromaticity of methyl coumalate, and the post transformation of this heterocyclic structure into other electron‐deficient arenes and heterocycles have addressed, in part, the challenging selectivity issues of the intermolecular cross‐RC reactions and the limited scope of iminium catalysis. 相似文献
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Hao Wu Li‐Li Zhang Zhi‐Qing Tian Dr. Yao‐Dong Huang Prof. Yong‐Mei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(5):1747-1753
Bispirooxindole derivatives containing three stereocenters, including two spiro quaternary centers, were synthesized in a high‐yielding, atypically rapid, and stereocontrolled cascade Michael–cyclization reaction between methyleneindolinones and isothiocyanato oxindoles catalyzed by a bi‐ or multifunctional organocatalyst. Mild conditions were used to construct bispirooxindoles with excellent enantio‐ and diastereomeric purities within less than 1 min. Catalyst reconfiguration offered access to the opposite enantiomer. This exceptionally highly efficient procedure will allow diversity‐oriented syntheses of this intriguing class of compounds with potential biological activities. 相似文献
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Organocatalytic,Asymmetric Eliminative [4+2] Cycloaddition of Allylidene Malononitriles with Enals: Rapid Entry to Cyclohexadiene‐Embedding Linear and Angular Polycycles 下载免费PDF全文
Dr. Nicoletta Brindani Dr. Gloria Rassu Dr. Luca Dell'Amico Dr. Vincenzo Zambrano Dr. Luigi Pinna Dr. Claudio Curti Dr. Andrea Sartori Prof. Dr. Lucia Battistini Prof. Dr. Giovanni Casiraghi Prof. Dr. Giorgio Pelosi Dr. Daniela Greco Prof. Dr. Franca Zanardi 《Angewandte Chemie (International ed. in English)》2015,54(25):7386-7390
A direct aminocatalytic synthesis has been developed for the chemo‐, regio‐, diastereo‐, and enantioselective construction of densely substituted polycyclic carbaldehydes containing fused cyclohexadiene rings. The chemistry utilizes, for the first time, remotely enolizable π‐extended allylidenemalononitriles as electron‐rich 1,3‐diene precursors in a direct eliminative [4+2] cycloaddition with both aromatic and aliphatic α,β‐unsaturated aldehydes. The generality of the process is demonstrated by approaching 6,6‐, 5,6‐, 7,6‐, 6,6,6‐, and 6,5,6‐fused ring systems, as well as biorelevant steroid‐like 6,6,6,6,5‐ and 6,6,6,5,6‐rings. A stepwise reaction mechanism for the key [4+2] addition is proposed as a domino bis‐vinylogous Michael/Michael/retro‐Michael reaction cascade. The utility of the malononitrile moiety as traceless activating group of the dicyano nucleophilic substrates is demonstrated. 相似文献
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Organocatalytic Asymmetric 1,6‐Addition/1,4‐Addition Sequence to 2,4‐Dienals for the Synthesis of Chiral Chromans 下载免费PDF全文
Pernille H. Poulsen Karla Santos Feu Bruno Matos Paz Prof. Dr. Frank Jensen Prof. Dr. Karl Anker Jørgensen 《Angewandte Chemie (International ed. in English)》2015,54(28):8203-8207
A novel asymmetric organocatalytic 1,6‐addition/1,4‐addition sequence to 2,4‐dienals is described. Based on a 1,6‐Friedel–Crafts/1,4‐oxa‐Michael cascade, the organocatalyst directs the reaction of hydroxyarenes with a vinylogous iminium‐ion intermediate to give only one out of four possible regioisomers, thus providing optically active chromans in high yields and 94–99 % ee. Furthermore, several transformations are presented, including the formation of an optically active macrocyclic lactam. Finally, the mechanism for the novel reaction is discussed based on computational studies. 相似文献
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Halland N Hansen T Jørgensen KA 《Angewandte Chemie (International ed. in English)》2003,42(40):4955-4957
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Jia-Hong Wu Siqiang Fang Xingtao Zheng Jiajia He Yi Ma Prof. Dr. Zhishan Su Prof. Dr. Tianli Wang 《Angewandte Chemie (International ed. in English)》2023,62(49):e202309515
The catalytic asymmetric synthesis of phosphorus-containing helicenes remains a formidable challenge, presumably due to the lack of rational design of substrates, right choice of reactions together with highly effective catalysis systems. Herein, we disclosed an efficient and practical DKR-involving (dynamic kinetic resolution) cascade strategy toward synthesizing a novel family of phosphorus-installing helicenes by peptide-mimic phosphonium salt (PPS) catalysis. The sequential process of PPS-catalyzed phospha-Michael attack and copper salt-facilitated aromatization led to the formation of unprecedented phosphorus-containing oxa[5]helicene scaffolds. A wide variety of substrates bearing an assortment of functional groups were compatible with this protocol, furnishing the expected helical compounds in high yields and excellent stereoselectivities. Additionally, the helical products could be conveniently elaborated to promising phosphine ligands with perfectly retained helical chirality, which turned out to be highly efficient chiral ligands in transition metal-catalyzed reactions. These findings not only expand the current library of phosphorus-containing helicenes but also offer insights to explore other challenging scaffolds with molecular chirality. 相似文献
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Dr. Taichi Kano Dr. Taiga Yurino Prof. Keiji Maruoka 《Angewandte Chemie (International ed. in English)》2013,52(44):11509-11512
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Chunzhang Wang Lijun Wang San Zeng Silong Xu Zhengjie He 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1548-1554
Abstract A new BINOL-derived chiral bifunctional phosphine has been designed and successfully prepared, which features a cyclic substructure of 1,3,5-diazaphosphinane. This chiral phosphine possesses good air stability in solid state, and it can be conveniently used as a relatively more nucleophilic phosphine organocatalyst. Preliminary investigations showed that it could generally afford fair to excellent yields but only modest enantioselectivity in the (aza)-Morita–Baylis–Hillman reactions of activated olefins such as ethyl acrylate and methyl vinyl ketone with aldehydes or imines. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus Sulfer and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.] 相似文献