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1.
Xihao Chang Jiayin Zhang Qinglin Zhang Prof. Dr. Chang Guo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18658-18662
An enantioselective bifunctional squaramide-catalyzed detrifluoroacetylative alkylation reaction has been developed under electrochemical conditions. The unified strategy based on this key tandem methodology has been divergently explored for the asymmetric synthesis of fluorine-containing target molecules with good stereocontrol (up to 95 % ee). Furthermore, this asymmetric catalytic reaction combines the benefits of electrosynthesis and organocatalysis for the preparation of biologically relevant products containing C-F tertiary stereogenic centers. 相似文献
2.
Diastereodivergent Asymmetric 1,4‐Addition of Oxindoles to Nitroolefins by Using Polyfunctional Nickel‐Hydrogen‐Bond‐Azolium Catalysts
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Dipl.‐Chem. Melanie Mechler Prof. Dr. René Peters 《Angewandte Chemie (International ed. in English)》2015,54(35):10303-10307
Diastereodivergency is a challenge for catalytic asymmetric synthesis. For many reaction types, the generation of one diastereomer is inherently preferred, while the other diastereomers are not directly accessible with high efficiency and require circuitous synthetic approaches. Overwriting the inherent preference by means of a catalyst requires control over the spatial positions of both reaction partners. We report a novel polyfunctional catalyst type in which a NiII‐bis(phenoxyimine) unit, free hydroxy groups, and an axially chiral bisimidazolium entity participate in the stereocontrol of the direct 1,4‐addition of oxindoles to nitroolefins. Both epimers of the 1,4‐adduct are accessible in excess on demand by changes to the ligand constitution and configuration. As the products have been reported to be valuable precursors to indole alkaloids, this method should allow access to their epimeric derivatives. 相似文献
3.
Córdova A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(8):1987-1997
The first proline-catalyzed direct catalytic asymmetric one-pot, three-component cross-Mannich reaction has been developed. The highly chemoselective reactions between two different unmodified aldehydes and one aromatic amine are new routes to 3-amino aldehydes with dr>19:1 and up to >99 % ee. The asymmetric cross-Mannich reactions are highly syn-selective and in several cases the two new carbon centers are formed with absolute stereocontrol. The reaction does not display nonlinear effects and therefore only one proline molecule is involved in the transition state. The reaction was also catalyzed with good selectivity by other proline derivatives. The Mannich products were converted into 3-amino alcohols and 2-aminobutane-1,4-diols with up to >99 % ee. The first one-pot, three-component, direct catalytic asymmetric cross-Mannich reactions between unmodified aldehydes, p-anisidine, and ethyl glyoxylate have been developed. The novel cross-Mannich reaction furnishes either enantiomer of unnatural alpha-amino acid derivatives in high yield and up to >99 % ee. The one-pot, three-component, direct catalytic asymmetric reactions were readily scaled up, operationally simple, and conductible in environmentally benign and wet solvents. The mechanism and stereochemistry of the proline-catalyzed, one-pot, three-component, asymmetric cross-Mannich reaction are also discussed. 相似文献
4.
The first catalytic asymmetric total synthesis of mycocerosic acid was achieved via the application of iterative enantioselective 1,4-addition reactions and allows for the efficient construction of 1,3-polymethyl arrays with full stereocontrol; further exemplified by the synthesis of tetramethyl-decanoic acid, a component of the preen-gland wax of the graylag goose, Anser anser. 相似文献
5.
Catalytic enantioselective 1,4-additions and tandem 1,4-addition-aldol reactions of dialkylzinc reagents to cyclopentene-3,5-dione monoacetals in the presence of an in situ generated Cu(OTf)(2)/chiral phosphoramidite catalyst result in highly functionalized cyclopentane building blocks with ee's up to 97%. A new synthesis of cyclopentene-3,5-dione monoacetals is presented as well as its use in a tandem 1,4-addition-aldol protocol for the catalytic asymmetric total synthesis of (-)-PGE(1) methyl ester. This synthesis represents a new approach to this class of natural products. By using only 3 mol % of an enantiomerically pure catalyst in the key step, the absolute configurations at three stereocenters of the basic structure of the PGE(1) are established at once. 相似文献
6.
A catalytic diastereo- and enantioselective method for tandem conjugate addition-aldol cyclization is described. This methodology enables the formation of five- and six-membered ring products from aromatic and aliphatic mono-enone mono-ketone precursors. Notably, in a single manipulation, three contiguous stereogenic centers are created with high levels of relative and absolute stereocontrol. 相似文献
7.
Córdova A Zou W Ibrahem I Reyes E Engqvist M Liao WW 《Chemical communications (Cambridge, England)》2005,(28):3586-3588
The linear amino acid-catalyzed direct asymmetric intermolecular aldol reaction is presented; simple amino acids such as alanine, valine, isoleucine, aspartate, alanine tetrazole and serine catalyzed the direct catalytic asymmetric intermolecular aldol reactions between unmodified ketones and aldehydes with excellent stereocontrol and furnished the corresponding aldol products in up to 98% yield and with up to > 99% ee. 相似文献
8.
Samson Afewerki Prof. Dr. Ismail Ibrahem Jonas Rydfjord Palle Breistein Prof. Dr. Armando Córdova 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(10):2972-2977
The first direct intermolecular regiospecific and highly enantioselective α‐allylic alkylation of linear aldehydes by a combination of achiral bench‐stable Pd0 complexes and simple chiral amines as co‐catalysts is disclosed. The co‐catalytic asymmetric chemoselective and regiospecific α‐allylic alkylation reaction is linked in tandem with in situ reduction to give the corresponding 2‐alkyl alcohols with high enantiomeric ratios (up to 98:2 e.r.; e.r.=enantiomeric ratio). It is also an expeditious entry to valuable 2‐alkyl substituted hemiacetals, 2‐alkyl‐butane‐1,4‐diols, and amines. The concise co‐catalytic asymmetric total syntheses of biologically active natural products (e.g., Arundic acid) are disclosed. 相似文献
9.
A set of enantiopure thiazolidine-based organocatalysts have been synthesized from l-cysteine, in a straightforward manner allowing numerous structural variations. In particular, organocatalyst 3a exhibits the highest catalytic performance working in an aqueous medium. It catalyzed the direct catalytic asymmetric intermolecular aldol reaction between unmodified ketones and an aldehyde with excellent stereocontrol and furnished the corresponding aldol products in up to 99% ee. Compound 3a also showed excellent asymmetric catalytic activity in the asymmetric Michael reaction (up to 99% ee). 相似文献
10.
Trost BM Hansmann MM Thaisrivongs DA 《Angewandte Chemie (International ed. in English)》2012,51(20):4950-4953
Activated: the title reaction proceeds with a broad range of nucleophiles and variously substituted 1,4-dienes under mild conditions, and provides direct access to the corresponding 1,3-diene-containing products with high regio- and stereocontrol (see scheme; 2,6-DMBQ=2,6-dimethylbenzoquinone, EWG=electron-withdrawing group). This is the first catalytic allylic C-H alkylation that proceeds in the absence of sulfoxide ligands. 相似文献
11.
Merging the catalytic asymmetric synthesis of di(allyl) ethers with ensuing olefin isomerization-Claisen rearrangement (ICR) reactions provides a convenient, two-step route to asymmetric aliphatic Claisen rearrangements from easily obtained starting materials. These reactions deliver the 2,3-disubstituted 4-pentenal derivatives characteristic of aliphatic Claisen rearrangements with excellent relative and absolute stereocontrol. A catalytic enantioselective synthesis of the (+)-calopin dimethyl ether demonstrates the utility of this reaction technology in asymmetric synthesis enterprises. 相似文献
12.
John R. Coombs Prof. James P. Morken 《Angewandte Chemie (International ed. in English)》2016,55(8):2636-2649
Terminal alkenes are readily available functional groups which appear in α‐olefins produced by the chemical industry, and they appear in the products of many contemporary synthetic reactions. While the organic transformations that apply to alkenes are amongst the most studied reactions in all of chemical synthesis, the number of reactions that apply to nonactivated terminal alkenes in a catalytic enantioselective fashion is small in number. This Minireview highlights the cases where stereocontrol in catalytic reactions of 1‐alkenes is high enough to be useful for asymmetric synthesis. 相似文献
13.
We have devised an expeditious, efficient, asymmetric synthesis of the C(33) – C(37) fragment of amphotericin B that proceeds in 14 steps and 16% overall yield from tiglic aldehyde ((E)‐2‐methylbut‐2‐enal) with complete stereocontrol. The route described herein relies on the application of recently developed methods in catalytic asymmetric synthesis for stereocontrol through enantio‐ and diastereoselective functionalization of a substituted sorbate derivative. 相似文献
14.
Copper‐Catalyzed Oxidative Dimerizations of 3‐N‐Hydroxy‐aminoprop‐1‐enes to form 1,4‐Dihydroxy‐2,3‐diaminocyclohexanes with C2 Symmetry
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Satish Ghorpade Prof. Dr. Rai‐Shung Liu 《Angewandte Chemie (International ed. in English)》2014,53(47):12885-12888
This work describes the one‐step construction of complex and important molecular frameworks through copper‐catalyzed oxidations of cheap tertiary amines. Copper‐catalyzed aerobic oxidations of N‐hydroxyaminopropenes to form C2‐symmetric N‐ and O‐functionalized cyclohexanes are described. Such catalytic oxidations proceed with remarkable stereocontrol and high efficiency. Reductive cleavage of the two N? O bonds of these products delivers 1,4‐dihydroxy‐2,3‐diaminocyclohexanes, which are important skeletons of several bioactive molecules. 相似文献
15.
Park PK O'Malley SJ Schmidt DR Leighton JL 《Journal of the American Chemical Society》2006,128(9):2796-2797
The first total synthesis of dolabelide D (or of any of the closely related dolabelides) has been achieved with a longest linear sequence of 17 steps. Key features of the synthesis include an application of the catalytic asymmetric silane alcoholysis, the tandem silylformylation-crotylsilylation, and a Brook-like 1,4-carbon to oxygen silyl migration. 相似文献
16.
《中国化学快报》2023,34(8):108105
1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural products. Especially, they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units independently. Recently, great efforts have been made to establish efficient protocols to achieve optically active 1,4-enynes. Considering the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described, here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing skeletons. According to the reaction types, this review is divided into five parts, including asymmetric allylic substitution, asymmetric propargylic substitution, asymmetric alkynylallylic substitution, asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones. 相似文献
17.
Zhi‐Chao Chen Zhi Chen Zhen‐Hong Yang Li Guo Wei Du Ying‐Chun Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15163-15167
Asymmetric reactions merging organocatalysis and metal catalysis significantly broaden the scope of organic synthesis. Nevertheless, the accomplishment of stereoselective annulations combining two types of dipole species, independently generated from the activations of organocatalysts and metal complexes, still remains as a challenging task. Now, Morita–Baylis–Hillman carbonates from isatins and carbamate‐functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes. The zwitterionic allylic ylides and 1,4‐π‐allyliridium dipoles formed in situ are assembled in a highly stereoselective [4+3] annulation pattern. Similar cooperative catalytic strategy could be applied for the reactions of Morita–Baylis–Hillman carbonates and vinyl aziridines, furnishing an asymmetric [3+3] annulation reaction also with excellent stereocontrol. 相似文献
18.
Dr. Daniel M. Wanner Patrick M. Becker Simon Suhr Dr. Nick Wannenmacher Dr. Slava Ziegler Justin Herrmann Dr. Felix Willig Julia Gabler Khushbu Jangid Dr. Juliane Schmid Andreas C. Hans Dr. Wolfgang Frey Prof. Dr. Biprajit Sarkar Prof. Dr. Johannes Kästner Prof. Dr. René Peters 《Angewandte Chemie (International ed. in English)》2023,62(36):e202307317
Pyrazolones represent an important structural motif in active pharmaceutical ingredients. Their asymmetric synthesis is thus widely studied. Still, a generally highly enantio- and diastereoselective 1,4-addition to nitroolefins providing products with adjacent stereocenters is elusive. In this article, a new polyfunctional CuII-1,2,3-triazolium-aryloxide catalyst is presented which enables this reaction type with high stereocontrol. DFT studies revealed that the triazolium stabilizes the transition state by hydrogen bonding between C(5)−H and the nitroolefin and verify a cooperative mode of activation. Moreover, they show that the catalyst adopts a rigid chiral cage/pore structure by intramolecular hydrogen bonding, by which stereocontrol is achieved. Control catalyst systems confirm the crucial role of the triazolium, aryloxide and CuII, requiring a sophisticated structural orchestration for high efficiency. The addition products were used to form pyrazolidinones by chemoselective C=N reduction. These heterocycles are shown to be valuable precursors toward β,γ’-diaminoamides by chemoselective nitro and N−N bond reductions. Morphological profiling using the Cell painting assay identified biological activities for the pyrazolidinones and suggest modulation of DNA synthesis as a potential mode of action. One product showed biological similarity to Camptothecin, a lead structure for cancer therapy. 相似文献
19.
Catalytic asymmetric 1,4-addition (conjugate addition; Michael addition) is one of the most powerful methods for carbon-carbon bond formation. Following the first efficient catalyst system developed by Feringa, which is composed of Cu(OTf)2 and phosphoramidite with dialkylzincs, a variety of chiral catalysts have been reported for the catalytic asymmetric conjugate addition. In this digest review, we will first summarize novel chiral ligands that work efficiently for cyclic and acyclic enones and demonstrate the wide applicability of Michael acceptors. We will also introduce unique phenomena that include the nonlinear effect and reversal of enantioselectivity. Organomagnesium reagents have also been used instead of organozincs. Finally, we introduce the recent examples of the synthesis of natural products based on the catalytic asymmetric reaction. The rare experimental studies into the mechanism of copper-catalyzed 1,4-addition reported by Kitamura and Noyori’s group are also introduced. 相似文献
20.
An asymmetric total synthesis of callipeltoside A has been accomplished highlighted by a catalytic enantioselective vinylogous aldol reaction and a boron-mediated anti-aldol reaction influenced by remote stereocontrol. 相似文献