共查询到20条相似文献,搜索用时 15 毫秒
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Kodai Kato Prof. Dr. Koji Hirano Prof. Dr. Masahiro Miura 《Angewandte Chemie (International ed. in English)》2016,55(46):14400-14404
A copper‐catalyzed regioselective and stereospecific aminoboration of vinylsilanes with bis(pinacolato)diboron (pinB‐Bpin) and hydroxylamines has been developed. In the presence of a CuCl/MeO‐dppbz catalyst, the boryl group and amino group are incorporated at the β position and α position, respectively, and the corresponding β‐boryl‐α‐aminosilanes are obtained with good diastereoselectivity. The boryl group is a good latent functional group, and subsequent manipulations provide a variety of β‐functionalized α‐aminosilanes of great potential in medicinal chemistry. Additionally, preliminary application to asymmetric catalysis is also described. 相似文献
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Kosuke Yamamoto Yutaro Tsuda Masami Kuriyama Yosuke Demizu Osamu Onomura 《化学:亚洲杂志》2020,15(6):840-844
A copper‐catalyzed enantioselective transformation of tris(hydroxymethyl)aminomethane‐derived aminotriols was developed to provide multisubstituted oxazolines with a tetrasubstituted carbon center. The present transformation consisted of sequential reactions involving mono‐sulfonylation of aminotriols, subsequent intramolecular cyclization to afford prochiral oxazoline diols, and sulfonylative asymmetric desymmetrization of resultant oxazoline diols. In addition, the kinetic resolution process would be involved in the sulfonylative asymmetric desymmetrization step, which would amplify the enantiopurities of the desired products. Various aminotriols were tolerated in the present reaction, affording the desired oxazolines in good to high yields with excellent enantioselectivities. The synthetic utility of the present reaction was demonstrated by the transformation of the optically active oxazoline into a chiral α‐tertiary amine motif. 相似文献
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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
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Carina I. Jette Z. Jaron Tong Ryan G. Hadt Brian M. Stoltz 《Angewandte Chemie (International ed. in English)》2020,59(5):2033-2038
Herein, we report a Cu‐catalyzed enantioselective allylic alkylation using a γ‐butyrolactone‐derived silyl ketene acetal. Critical to the development of this work was the identification of a novel mono‐picolinamide ligand with the appropriate steric and electronic properties to afford the desired products in high yield (up to 96 %) and high ee (up to 95 %). Aryl, aliphatic, and unsubstituted allylic chlorides bearing a broad range of functionality are well‐tolerated. Spectroscopic studies reveal that a CuI species is likely the active catalyst, and DFT calculations suggest ligand sterics play an important role in determining Cu coordination and thus catalyst geometry. 相似文献
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Xueling Mo Bin Chen Guozhu Zhang 《Angewandte Chemie (International ed. in English)》2020,59(33):13998-14002
An asymmetric copper‐catalyzed Sonogashira type coupling between alkynes and α‐bromoamides has been developed. This method represents a facile approach to synthetically useful β, γ‐alkynyl amides from two readily available starting materials in a highly enantioselective manner. A Bisoxazoline diphenylanaline (BOPA) serves as the effective chiral ligand. Preliminary mechanistic studies support the formation of alkyl radical species . 相似文献
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Ge Zhang Yanfei Li Ying Wang Qian Zhang Tao Xiong Qian Zhang 《Angewandte Chemie (International ed. in English)》2020,59(29):11927-11931
The catalytic asymmetric creation of silanes with silicon stereocenters is a long‐sought but underdeveloped topic, and only a handful of examples have been reported. Moreover, the construction of chiral silanes containing (more than) two stereocenters is a more arduous task and remains unexploited. We herein report an unprecedented copper‐catalyzed desymmetrizing protoboration of divinyl‐substituted silanes with bis(pinacolato)diboron (B2pin2). This method enables the facile preparation of an array of enantiomerically enriched boronate‐substituted organosilanes bearing contiguous silicon and carbon stereocenters with exclusive regioselectivity and generally excellent diastereo‐ and enantioselectivity. 相似文献
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Weiming Yuan Liu Song Prof. Dr. Shengming Ma 《Angewandte Chemie (International ed. in English)》2016,55(9):3140-3143
A highly regio‐ and stereoselective copper‐catalyzed borylcupration of 1,2‐allenylsilanes affords an unexpected regioreversed allylic boronate bearing an extra C?Si bond at the 3‐position, with a thermodynamically disfavored Z geometry. Such stereodefined allylic boronates containing an extra alkenyl silane moiety are very useful organodimetallic reagents for organic synthesis. 相似文献
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A detailed investigation of the reactions of PhSO2CF2H and PhSO2CH2F with (E)‐chalcone (=(E)‐1,3‐diphenylprop‐2‐en‐1‐one) at low temperatures revealed that these two reactions were kinetically controlled, and the ratios of 1,2‐ vs. 1,4‐adducts, which did not change much over time at these temperatures, reflect the relative rates of the two reaction pathways. The controlled experiments of converting the PhSO2CF2‐ and PhSO2CHF‐substituted 1,2‐adducts to 1,4‐adducts showed that these isomerizations are not favored due to the low stability and hard‐soft nature of PhSO2CF and PhSO2CHF? anions. Moreover, taking advantage of the remarkable stability and softness of (PhSO2)2CF? anion, an efficient thermodynamically controlled isomerization of (PhSO2)2CF‐substituted 1,2‐adduct to 1,4‐adduct was achieved for the first time. 相似文献
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《中国化学》2017,35(11):1665-1668
An efficient method for Cu‐catalyzed decarboxylative trifluoromethylation of β ‐ketoacids to achieve α ‐trifluoromethyl ketones was developed. A wide variety of synthetically useful α ‐trifluoromethyl ketones were obtained in modest to good yields under mild reaction conditions. The present method also exhibits good functional‐group compatibility. 相似文献
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Enantioselective Synthesis of α‐Aminosilanes by Copper‐Catalyzed Hydroamination of Vinylsilanes 下载免费PDF全文
Nootaree Niljianskul Dr. Shaolin Zhu Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2015,54(5):1638-1641
The synthesis of α‐aminosilanes by a highly enantio‐ and regioselective copper‐catalyzed hydroamination of vinylsilanes is reported. The system employs Cu‐DTBM‐SEGPHOS as the catalyst, diethoxymethylsilane as the stoichiometric reductant, and O‐benzoylhydroxylamines as the electrophilic nitrogen source. This hydroamination reaction is compatible with differentially substituted vinylsilanes, thus providing access to amino acid mimics and other valuable chiral organosilicon compounds. 相似文献
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Dr. Qing‐Wei Zhang Kun An Li‐Chuan Liu Shuangxi Guo Chenran Jiang Dr. Huifang Guo Prof. Dr. Wei He 《Angewandte Chemie (International ed. in English)》2016,55(21):6319-6323
Silacyclobutane was discovered to be an efficient C?H bond silylation reagent. Under the catalysis of RhI/TMS‐segphos, silacyclobutane undergoes sequential C?Si/C?H bond activations, affording a series of π‐conjugated siloles in high yields and regioselectivities. The catalytic cycle was proposed to involve a rarely documented endocyclic β‐hydride elimination of five‐membered metallacycles, which after reductive elimination gave rise to a Si?RhI species that is capable of C?H activation. 相似文献
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Asymmetric Copper‐Catalyzed Vinylogous Mukaiyama Michael Addition of Cyclic Dienol Silanes to Unsaturated α‐Keto Phosphonates 下载免费PDF全文
Anne‐Dorothee Steinkamp Marcus Frings Dr. Isabelle Thomé Dr. Ingo Schiffers Prof. Dr. Carsten Bolm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7705-7708
A highly stereoselective vinylogous Mukaiyama Michael reaction (VMMR) leading to α‐keto phosphonate‐containing γ‐butenolides with two stereogenic centers is described. The presented transformation is catalyzed by a combination of a commercially available C2‐symmetric bisoxazoline (BOX) ligand and a copper salt and tolerates a variety of nucleophiles and electrophiles. The stereoselectivities of the reactions are good to excellent and the products are obtained in moderate to high yields. 相似文献
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Copper‐Catalyzed Oxidative Reaction of β‐Keto Sulfones with Alcohols via C−S Bond Cleavage: Reaction Development and Mechanism Study 下载免费PDF全文
Yang Wang Zhenghang Qi Jiaqi Tian Dr. Jie Zhou Xiaochen Wang Prof. Dr. Jianlin Han Prof. Dr. Jing Ma Prof. Dr. Yi Pan 《化学:亚洲杂志》2018,13(4):404-408
A Cu‐catalyzed cascade oxidative radical process of β‐keto sulfones with alcohols has been achieved by using oxygen as an oxidant. In this reaction, β‐keto sulfones were converted into sulfinate esters under the oxidative conditions via cleavage of C?S bond. Experimental and computational studies demonstrate that a new pathway is involved in this reaction, which proceeds through the formation of the key four‐coordinated CuII intermediate, O?O bond homolysis induced C?S bond cleavage and Cu‐catalyzed esterification to form the final products. This reaction provides a new strategy to sulfonate esters and enriches the research content of C?S bond cleavage and transformations. 相似文献