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1.
Rueping M Sundén H Sugiono E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(12):3649-3653
A multicatalytic system consisting of tetrapropylammonium perruthenate/N-methylmorpholine N-oxide (TPAP/NMO) as oxidant, and diarylprolinol TMS-ether as chiral amine catalyst, has been developed and applied in the efficient construction of valuable chiral molecules. The one-pot domino reactions elaborated in the present study are based on the in situ generation of α,β-unsaturated aldehydes from allylic alcohols and their subsequent use in various asymmetric transformations (e.g., cyclopropanation, Michael addition, Michael addition/acetalization). TPAP as a substrate-selective redox catalyst is well tolerated by the amine catalyst and the domino reactions proceed in good yields and high enantioselectivities. The compatibility of metal and organocatalysis presented herein widens the scope of asymmetric iminium catalysis. 相似文献
2.
Asymmetric Michael Addition/Intramolecular Cyclization Catalyzed by Bifunctional Tertiary Amine–Squaramides: Construction of Chiral 2‐Amino‐4H‐chromene‐3‐Carbonitrile Derivatives 下载免费PDF全文
The efficient asymmetric Michael addition/intramolecular cyclization of malononitrile with dienones catalyzed by a chiral bifunctional tertiary amine–squaramide catalyst for the synthesis of chiral 2‐amino‐4H‐chromene‐3‐carbonitrile derivatives was developed. The corresponding products were obtained in good to excellent yields (up to 99 %) with excellent enantioselectivities (up to 98 % ee) for most of the bisarylidenecyclopentanones. 相似文献
3.
Mithun Kumar Debnath Wako Oyama Yuya Ono Takuya Sugimoto Rina Watanabe Naoki Haraguchi 《Journal of polymer science. Part A, Polymer chemistry》2021,59(11):1072-1083
Polymer microsphere-supported chiral pyrrolidine catalysts were successfully synthesized by a precipitation polymerization incorporating a methacrylate monomer bearing chiral N-Boc-pyrrolidine moiety, followed by removal of the N-Boc groups. The resulting polymeric catalysts were applied to the asymmetric Michael addition reactions of aldehydes with alkyl vinyl ketones. The effects of the comonomer, the molar ratios within the catalyst, the catalyst loading, the temperature, and the solvent on the catalytic performance were investigated in detail. The reactions were found to proceed smoothly in the absence of a solvent. A hydrophobic polystyrene-based chiral pyrrolidine catalyst exhibited high reactivity (up to 97% yield) and enantioselectivity (up to 95% ee) during these reactions. The catalyst could also be recovered and reused up to five times without significant loss of activity. 相似文献
4.
Wei Yang Dr. Ke‐Zhi Jiang Xing Lu Hua‐Meng Yang Dr. Li Li Prof. Dr. Yixin Lu Prof. Dr. Li‐Wen Xu 《化学:亚洲杂志》2013,8(6):1182-1190
A combined catalyst system of a cinchonidine‐derived primary amine and triphenylphosphine (CD‐NH2/PPh3) exhibited high catalytic performance in the Michael reaction of aldehydes with maleimides, thereby affording the corresponding functionalized aldehydes in excellent yields (up to 99 %) and enantioselectivities (>99 % ee). More interestingly, the significance of the phosphine in enhancing the enantioselectivities in the chiral‐primary‐amine‐catalyzed Michael reaction was revealed. Furthermore, we explored the origin of the reaction mechanism in the Michael addition promoted by the dual organocatalytic system. On the basis of experimental results and spectroscopic analysis, such as UV/Vis, fluorescence emission (FL), NMR, and circular dichroism (CD) spectroscopy, as well as ESI‐MS, we found that the molecular assembly of phosphine and primary amine played a crucial role in this enantioselective reaction, in which a possible supramolecular complex was formed as an effective chiral catalyst through noncovalent molecular interactions of a cinchona alkaloid‐derived primary amine with triphenylphosphine. 相似文献
5.
Palladacycle Catalyzed Asymmetric PH Addition of Diarylphosphines to N‐Enoyl Phthalimides 下载免费PDF全文
Renta Jonathan Chew Dr. Yunpeng Lu Yu‐Xiang Jia Bin‐Bin Li Esther Hui Yen Wong Rosanne Goh Dr. Yongxin Li Dr. Yinhua Huang Dr. Sumod Appukuttan Pullarkat Prof. Dr. Pak‐Hing Leung 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14514-14517
The first asymmetric phospha‐Michael addition of diarylphosphines to N‐enoyl phthalimides has been developed in the presence of a chiral palladacycle catalyst. A library of free chiral tertiary phosphine adducts were directly obtained with excellent yields and enantioselectivities. Products can be subsequently functionalized to afford β‐phosphinoamides, the direct preparation of which from cinnamides has been notoriously challenging. 相似文献
6.
Dr. Hayato Ishikawa Takaki Suzuki Dr. Hideo Orita Dr. Tadafumi Uchimaru Prof. Dr. Yujiro Hayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(42):12616-12626
The efficient asymmetric total synthesis of (?)‐oseltamivir, an antiviral reagent, has been accomplished by using two “one‐pot” reaction sequences, with excellent overall yield (60 %) and only one required purification by column chromatography. The first one‐pot reaction sequence consists of a diphenylprolinol silyl ether mediated asymmetric Michael reaction, a domino Michael reaction/Horner–Wadsworth–Emmons reaction combined with retro‐aldol/Horner–Wadsworth–Emmons reaction and retro Michael reactions, a thiol Michael reaction, and a base‐catalyzed isomerization. Six reactions can be successfully conducted in the second one‐pot reaction sequence; these are deprotection of a tert‐butyl ester and its conversion into an acyl chloride then an acyl azide, Curtius rearrangement, amide formation, reduction of a nitro group into an amine, and a retro Michael reaction of a thiol moiety. A column‐free synthesis of (?)‐oseltamivir has also been established. 相似文献
7.
Tomoyuki Shibuguchi Hisashi Mihara Akiyoshi Kuramochi Takashi Ohshima Dr. Masakatsu Shibasaki Prof. Dr. 《化学:亚洲杂志》2007,2(6):794-801
Catalytic asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with chiral two‐center organocatalysts, tartrate‐derived diammonium salts (TaDiASs), are described. On the basis of conformational studies, optimized TaDiASs with a 2,6‐disubstituted cyclohexane spiroacetal were newly designed. These TaDiASs catalyzed the asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with higher enantioselectivity than previous catalysts. In the Mannich‐type reaction, aromatic N‐Boc‐protected imines (Boc=tert‐butoxycarbonyl) as well as enolizable alkyl imines were applicable. As a synthetic application of the catalytic asymmetric Mannich‐type reaction with the optimized TaDiASs, we developed a catalytic asymmetric total synthesis of (+)‐nemonapride, which is an antipsychotic agent. 相似文献
8.
Intermolecular Asymmetric Carboesterification of Alkenes by Using Chiral Amine Auxiliaries under O2: Synthesis of Enantioenriched α‐Methylene‐γ‐Lactones through Chloropalladation of Alkynes 下载免费PDF全文
Zhenming Zhang Dr. Wanqing Wu Jianhua Liao Jianxiao Li Prof. Dr. Huanfeng Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6708-6712
Herein, the first example of chloropalladation‐initiated asymmetric intermolecular carboesterification of alkenes with alkynes by using chiral amine auxiliaries is reported. The use of (1S,2S)‐N1,N1‐dimethylcyclohexane‐1,2‐diamine auxiliaries is essential for providing α‐methylene‐γ‐lactones products in moderate to high yields and excellent enantioselectivities at room temperature. Moreover, the chiral amine auxiliaries can be readily removed by hydrolysis during the reaction process to keep the absolute configuration. This oxygen‐ and water‐promoted asymmetric reaction opens a new window to study asymmetric processes in halopalladation reactions. 相似文献
9.
Highly Enantioselective Tandem Michael Addition of Tryptamine‐Derived Oxindoles to Alkynones: Concise Synthesis of Strychnos Alkaloids 下载免费PDF全文
Weigang He Jiadong Hu Pengyan Wang Le Chen Kai Ji Siyu Yang Yin Li Zhilong Xie Prof. Dr. Weiqing Xie 《Angewandte Chemie (International ed. in English)》2018,57(14):3806-3809
A highly enantioselective tandem Michael addition of tryptamine‐derived oxindoles to alkynones was developed by taking advantage of a chiral N,N′‐dioxide Sc(OTf)3 catalyst. The reaction enables the facile preparation of enantioenriched spiro[pyrrolidine‐3,3′‐oxindole] compounds, which provides a novel strategy for the synthesis of monoterpenoid indole alkaloids. As a demonstration, the asymmetric synthesis of strychnos alkaloids [(?)‐tubifoline, (?)‐tubifolidine, (?)‐dehydrotubifoline] was achieved in 10–11 steps. 相似文献
10.
《Tetrahedron: Asymmetry》2014,25(20-21):1376-1382
An asymmetric two-step approach toward the synthesis of chiral cyclopropane-fused tetrahydroquinolines is described. In this synthesis, an asymmetric organocatalytic Michael/alkylation domino reaction of dialkyl bromomalonates with o-N-protected aminophenyl α,β-unsaturated aldehydes allows the process to proceed efficiently to afford the corresponding 2-formylcyclopropane products in good yields and with high enantioselectivities (up to 97% ee). In addition, a one-pot procedure for the DBU-mediated aza-cyclization of the 2-formylcyclopropane adducts was applied for the formation of chiral cyclopropane-fused tetrahydroquinolines. 相似文献
11.
Xiying Zhang Wangbin Wu Weidi Cao Han Yu Xi Xu Xiaohua Liu Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2020,59(12):4846-4850
Highly efficient asymmetric intermolecular radical‐polar crossover reactions were realized by combining a chiral N,N′‐dioxide/NiII complex catalyst with Ag2O under mild reaction conditions. Various terminal alkenes and indanonecarboxamides/esters underwent radical addition/cyclization reactions to afford spiro‐iminolactones and spirolactones with good to excellent yields (up to 99 %) and enantioselectivities (up to 97 % ee). Furthermore, a range of different radical‐mediated oxidation/elimination or epoxide ring‐opening products were obtained under mild reaction conditions. The Lewis acid catalysts exhibited excellent performance and precluded the strong background reaction. 相似文献
12.
Takasuke Mukaiyama Dr. Hayato Ishikawa Dr. Hiroyuki Koshino Prof. Dr. Yujiro Hayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(52):17789-17800
The one‐pot sequential synthesis of (?)‐oseltamivir has been achieved without evaporation or solvent exchange in 36 % yield over seven reactions. The key step was the asymmetric Michael reaction of pentan‐3‐yloxyacetaldehyde with (Z)‐N‐2‐nitroethenylacetamide, catalyzed by a diphenylprolinol silyl ether. The use of a bulky O‐silyl‐substituted diphenylprolinol catalyst, chlorobenzene as a solvent, and HCO2H as an acid additive, were key to produce the first Michael adduct in both excellent yield and excellent diastereo‐ and enantioselectivity. Investigation into the effect of acid demonstrated that an acid additive accelerates not only the E–Z isomerization of the enamines derived from pentan‐3‐yloxyacetaldehyde with diphenylprolinol silyl ether, but also ring opening of the cyclobutane intermediate and the addition reaction of the enamine to (Z)‐N‐2‐nitroethenylacetamide. The transition‐state model for the Michael reaction of pentan‐3‐yloxyacetaldehyde with (Z)‐N‐2‐nitroethenylacetamide was proposed by consideration of the absolute configuration of the major and minor isomers of the Michael product with the results of the Michael reaction of pentan‐3‐yloxyacetaldehyde with phenylmaleimide and naphthoquinone. 相似文献
13.
An efficient synthetic procedure for the functionalized spiro[furan‐3,3′‐indoline] derivatives was successfully developed by domino reactions of N‐phenacylpyridinium bromides or N‐ethoxycarbonylmethylenepyridinium bromide with isatinylidene acetoacetate in the presence of triethylamine in ethanol at room temperature. The mechanism included sequential Michael addition of the in situ generated pyridinium ylide and intramolecular substitution of enolate. 相似文献
14.
Aromatic Interactions in Organocatalyst Design: Augmenting Selectivity Reversal in Iminium Ion Activation 下载免费PDF全文
Dr. Constantin Daniliuc Dr. W. Bernd Schweizer Prof. Dr. Ryan Gilmour 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10031-10038
Substituting N‐methylpyrrole for N‐methyindole in secondary‐amine‐catalysed Friedel–Crafts reactions leads to a curious erosion of enantioselectivity. In extreme cases, this substrate dependence can lead to an inversion in the sense of enantioinduction. Indeed, these closely similar transformations require two structurally distinct catalysts to obtain comparable selectivities. Herein a focussed molecular editing study is disclosed to illuminate the structural features responsible for this disparity, and thus identify lead catalyst structures to further exploit this selectivity reversal. Key to effective catalyst re‐engineering was delineating the non‐covalent interactions that manifest themselves in conformation. Herein we disclose preliminary validation that intermolecular aromatic (CH–π and cation–π) interactions between the incipient iminium cation and the indole ring system is key to rationalising selectivity reversal. This is absent in the N‐methylpyrrole alkylation, thus forming the basis of two competing enantio‐induction pathways. A simple L ‐valine catalyst has been developed that significantly augments this interaction. 相似文献
15.
Ketang Liu Ronghua Jin Tanyu Cheng Xiangming Xu Fei Gao Prof. Guohua Liu Prof. Hexing Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(48):15546-15553
A functionalized periodic mesoporous organosilica with incorporated chiral bis(cyclohexyldiamine)‐based NiII complexes within the silica framework was developed by the co‐condensation of (1R,2R)‐cyclohexyldiamine‐derived silane and ethylene‐bridge silane, followed by the complexation of NiBr2 in the presence of (1R,2R)‐N,N′‐dibenzylcyclohexyldiamine. Structural characterization by XRD, nitrogen sorption, and TEM disclosed its orderly mesostructure, and FTIR and solid‐state NMR spectroscopy demonstrated the incorporation of well‐defined single‐site bis(cyclohexyldiamine)‐based NiII active centers within periodic mesoporous organosilica. As a chiral heterogeneous catalyst, this functionalized periodic mesoporous organosilica showed high catalytic activity and excellent enantioselectivity in the asymmetric Michael addition of 1,3‐dicarbonyl compounds to nitroalkenes, comparable to those with homogeneous catalysts. In particular, this heterogeneous catalyst could be recovered easily and reused repeatedly up to nine times without obviously affecting its enantioselectivity, thus showing good potential for industrial applications. 相似文献
16.
Takashi Tozawa Dr. Hitoshi Nagao Yoshinobu Yamane Teruaki Mukaiyama Prof. Dr. 《化学:亚洲杂志》2007,2(1):123-134
Chiral quaternary ammonium phenoxides were readily prepared from commercially available cinchona alkaloids and proved to be useful new asymmetric organocatalysts. Among various chiral quaternary ammonium phenoxides, a cinchonidine‐derived catalyst that bears both a sterically hindered N1‐9‐anthracenylmethyl group and a strongly electron withdrawing 9‐O‐3,5‐bis(trifluoromethyl)benzyl group were found to be highly effective for the Michael addition of ketene silyl acetals (derived from phenyl carboxylates) and α,β‐unsaturated ketones followed by lactonization. Optically active 3,4‐dihydropyran‐2‐one derivatives were obtained in high yields with excellent control of enantio‐ and diastereoselectivity. This catalyst can be handled in air and stored at room temperature in a sealed bottle without decomposition for at least one month. 相似文献
17.
Highly Diastereo‐ and Enantioselective Michael Addition of Nitroalkanes to 2‐Enoyl‐Pyridine N‐Oxides Catalyzed by Scandium(III)/Copper(II) Complexes 下载免费PDF全文
Lijun Li Sheng Zhang Yanbin Hu Yanan Li Chong Li Prof. Zhenggen Zha Prof. Dr. Zhiyong Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(37):12885-12888
A C2‐symmetric Schiff‐base ligand, derived from tridentate‐Schiff‐base, was developed and successfully applied to the asymmetric Michael addition of nitroalkanes to 2‐enoyl‐pyridine N‐oxides. With this newly catalytic system, an unprecedented diastereoselectivity was obtained in the asymmetric Michael addition of nitroalkanes to 2‐enoyl‐pyridine N‐oxides. In addition, a switch in enantioselectivity was achieved by using this newly catalytic system and our previous catalyst. After a facile reduction, the optically active adduct was converted to a biologically active dihydro‐2H‐pyrrol 4 a . Furthermore, a connection of two tridentate‐Schiff‐base subunits proved to be an effective strategy in ligand design. 相似文献
18.
Facile Synthesis of Chiral Spirooxindole‐Based Isotetronic Acids and 5‐1H‐Pyrrol‐2‐ones through Cascade Reactions with Bifunctional Organocatalysts 下载免费PDF全文
Wengang Guo Xu Wang Dr. Boyu Zhang Shuai Shen Dr. Xin Zhou Peng Wang Prof. Yan Liu Prof. Can Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8545-8550
Unprecedented organocatalyzed asymmetric cascade reactions have been developed for the facile synthesis of chiral spirooxindole‐based isotetronic acids and 5‐1H‐pyrrol‐2‐ones.The asymmetric 1,2‐addition reactions of α‐ketoesters to isatins and imines by using an acid–base bifunctional 6′‐OH cinchona alkaloid catalyst, followed by cyclization and enolization of the resulting adducts, gave chiral spiroisotetronic acids and 5‐1H‐pyrrol‐2‐ones, respectively, in excellent optical purities (up to 98 % ee). FT‐IR analysis supported the existence of hydrogen‐bonding interaction between the 6′‐OH group of the cinchona catalyst and an isatin carbonyl group, an interaction that might be crucial for catalyst activity and stereocontrol. 相似文献
19.
Asymmetric Synthesis of Spirocyclic β‐Lactams through Copper‐Catalyzed Kinugasa/Michael Domino Reactions 下载免费PDF全文
Tao Shu Long Zhao Sun Li Dr. Xiang‐Yu Chen Dr. Carolina von Essen Prof. Dr. Kari Rissanen Prof. Dr. Dieter Enders 《Angewandte Chemie (International ed. in English)》2018,57(34):10985-10988
The first copper‐catalyzed highly chemo‐, regio‐, diastereo‐, and enantioselective Kinugasa/Michael domino reaction for the desymmetrization of prochiral cyclohexadienones is described. In the presence of a chiral copper catalyst, alkyne‐tethered cyclohexadienones couple with nitrones to generate the chiral spirocyclic lactams with excellent stereoselectivity (up to 97 % ee, >20:1 dr). The new method provides direct access to versatile highly functionalized spirocyclic β‐lactams possessing four contiguous stereocenters, including one quaternary and one tetra‐substituted stereocenter. 相似文献
20.
Copper‐Catalyzed Domino Synthesis of 2‐Imino‐1H‐imidazol‐5(2H)‐ones and Quinoxalines Involving CC Bond Cleavage with a 1,3‐Dicarbonyl Unit as a Leaving Group 下载免费PDF全文
Yan Yang Fan Ni Wen‐Ming Shu Prof. An‐Xin Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11776-11782
Although 2‐imino‐1H‐imidazol‐5(2H)‐ones have important biological activities in metabolism, their synthesis has rarely been investigated. Quinoxalines as “privileged scaffolds” in medicinal chemistry have been extensively investigated, but the development of novel and efficient synthetic methods remains very attractive. Herein, we have developed two copper‐catalyzed domino reactions for the synthesis of 2‐imino‐1H‐imidazol‐5(2H)‐ones and quinoxalines involving C?C bond‐cleavage with a 1,3‐dicarbonyl unit as a leaving group. The domino sequence for the synthesis of 2‐imino‐1H‐imidazol‐5(2H)‐ones includes aza‐Michael addition, intramolecular cyclization, C?C bond‐cleavage, 1,2‐rearrangement, and aerobic dehydrogenation reaction, whereas the domino sequence for the synthesis of quinoxalines includes aza‐Michael addition, intramolecular cyclization, elimination reaction, and C?C bond‐cleavage reaction. The two domino reactions have significant advantages including high efficiency, mild reaction conditions, and high tolerance of various functional groups. 相似文献