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1.
Wen-Wen Zhang Su-Lei Zhang Bi-Jie Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(17):6941-6947
Chiral propargyl amines are valuable synthetic intermediates for the preparation of biologically active compounds and functionalized amines. Catalytic methods to access propargyl amines containing vicinal stereocenters with high diastereoselectivity are particularly rare. We report an unprecedented strategy for the synthesis of enantioenriched propargyl amines with two stereogenic centres. An iridium complex, ligated by a phosphoramidite ligand, catalyzes the hydroalkynylation of β,β-disubstituted enamides to afford propargyl amides in a highly regio-, diastereo-, and enantioselective fashion. Stereodivergent synthesis of all four possible stereoisomers was achieved using this strategy. 相似文献
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Lujia Zhou Sanliang Li Bing Xu Danting Ji Lizuo Wu Yu Liu Zhan‐Ming Zhang Junliang Zhang 《Angewandte Chemie (International ed. in English)》2020,59(7):2769-2775
Sonogashira‐type cross‐couplings are one of the most significant alkynylations in organic chemistry. One of the first palladium‐catalyzed intramolecular Heck/Sonogashira reactions of alkenes with terminal alkynes is now reported. With this method, a variety of uniquely substituted chiral benzene‐fused heterocycles bearing a propargyl‐substituted all‐carbon quaternary stereocenter were obtained in a straightforward, high‐yielding, and highly stereoselective manner under mild conditions. Salient features of this process include the use of readily available substrates, high selectivities, a broad substrate scope as well as versatile product functionalizations. 相似文献
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Highly Enantioselective Direct Synthesis of Endocyclic Vicinal Diamines through Chiral Ru(diamine)‐Catalyzed Hydrogenation of 2,2′‐Bisquinoline Derivatives 下载免费PDF全文
Wenpeng Ma Jianwei Zhang Cong Xu Fei Chen Yan‐Mei He Prof. Dr. Qing‐Hua Fan 《Angewandte Chemie (International ed. in English)》2016,55(41):12891-12894
An asymmetric hydrogenation of 2,2′‐bisquinoline and bisquinoxaline derivatives, catalyzed by chiral cationic ruthenium diamine complexes, was developed. A broad range of chiral endocyclic vicinal diamines were obtained in high yields with excellent diastereo‐ and enantioselectivity (up to 93:7 dl/meso and >99 % ee). These chiral diamines could be easily transformed into a new class of chiral N‐heterocyclic carbenes (NHCs), which are important but difficult to access. 相似文献
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Copper‐Catalyzed Highly Stereoselective Trifluoromethylation and Difluoroalkylation of Secondary Propargyl Sulfonates 下载免费PDF全文
Xing Gao Yu‐Lan Xiao Xiaolong Wan Prof. Dr. Xingang Zhang 《Angewandte Chemie (International ed. in English)》2018,57(12):3187-3191
It is challenging to stereoselectively introduce a trifluoromethyl group (CF3) into organic molecules. To date, only limited strategies involving direct asymmetric trifluoromethylation have been reported. Herein, we describe a new strategy for direct asymmetric trifluoromethylation through the copper‐catalyzed stereospecific trifluoromethylation of optically active secondary propargyl sulfonates. The reaction enables propargylic trifluoromethylation with high regioselectivity and stereoselectivity. The reaction could also be extended to stereospecific propargylic difluoroalkylation. Transformations of the resulting enantiomerically enriched fluoroalkylated alkynes led to a variety of chiral fluoroalkylated compounds, thus providing a useful protocol for applications in the synthesis of fluorinated complexes. 相似文献
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Jiang‐Chun Zhong Dr. Shi‐Cong Hou Dr. Qing‐Hua Bian Dr. Min‐Min Yin Dr. Ri‐Song Na Bing Zheng Zhi‐Yuan Li Shang‐Zhong Liu Prof. Min Wang Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(13):3069-3071
Meeting the challenge : The zinc/amino alcohol catalyzed enantioselective addition of terminal alkynes to aldehydes is effective with both phenylacetylene and methyl propiolate, leading to chiral secondary propargyl alcohols with very high enantioselectivity (see scheme).
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Catalytic Enantioselective Nazarov Cyclization: Construction of Vicinal All‐Carbon‐Atom Quaternary Stereocenters 下载免费PDF全文
Anais Jolit Dr. Patrick M. Walleser Dr. Glenn P. A. Yap Prof. Dr. Marcus A. Tius 《Angewandte Chemie (International ed. in English)》2014,53(24):6180-6183
The diastereoselective asymmetric synthesis of vicinal all‐carbon‐atom quaternary stereocenters is a challenging problem in organic synthesis for which only few solutions have been described. A catalytic asymmetric Nazarov cyclization of fully substituted dienones that provides cyclopentenone derivatives with vicinal quaternary stereocenters in high optical purity and as single diastereoisomers is now reported. 相似文献
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Gaochao Huang Dr. Zengsheng Yin Prof. Dr. Xingang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11992-11998
A general and efficient method for the highly enantioselective alkynylation of ketoimines through a zinc/1,1′‐bi‐2‐naphthol (BINOL)‐catalyzed process has been developed. A variety of ketoimines, including α‐fluoroalkyl α‐imine esters, α‐aryl α‐imine esters, and trifluoromethyl aryl ketoimines, are applicable and provide their corresponding quaternary propargyl amines in excellent yields with high ee values (up to 99 % ee). Both the steric and electronic effects of substituents at the 3,3′ positions of BINOL are critical for the reaction efficiency and enantioselectivity. To demonstrate the usefulness of the method, (R)‐α‐CF3 α‐proline has been prepared in a highly efficient manner. The notable features of this protocol are its broad substrate scope, high reaction efficiency (up to 99 %) and enantioselectivity (up to 99 % ee), low catalyst loading (5 mol % of BINOL derivative), and mild reaction conditions. 相似文献
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Enantioselective Synthesis of Vicinal All‐Carbon Quaternary Centers via Iridium‐Catalyzed Allylic Alkylation 下载免费PDF全文
Dr. J. Caleb Hethcox Samantha E. Shockley Prof. Dr. Brian M. Stoltz 《Angewandte Chemie (International ed. in English)》2018,57(28):8664-8667
The development of the first enantioselective transition‐metal‐catalyzed allylic alkylation providing access to acyclic products bearing vicinal all‐carbon quaternary centers is disclosed. The iridium‐catalyzed allylic alkylation reaction proceeds with excellent yields and selectivities for a range of malononitrile‐derived nucleophiles and trisubstituted allylic electrophiles. The utility of these sterically congested products is explored through a series of diverse chemo‐ and diastereoselective product transformations to afford a number of highly valuable, densely functionalized building blocks, including those containing vicinal all‐carbon quaternary stereocenters. 相似文献
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Iridium‐Catalyzed Enantioselective Hydroalkynylation of Enamides for the Synthesis of Homopropargyl Amides 下载免费PDF全文
Prof. Dr. Bi‐Jie Li 《Angewandte Chemie (International ed. in English)》2016,55(31):9007-9011
Reported is an iridium‐catalyzed asymmetric hydroalkynylation of enamides with terminal alkynes. The reaction occurs regioselectively at the β‐position of an enamide to produce homopropargyl amides. Good to high enantioselectivity was observed with an iridium complex ligated by a chiral bis(phosphine) ligand. This method provides a straightforward route to synthesize chiral homopropargyl amides with a stereocenter β to the amide. 相似文献
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Ernest Salomó Dr. Sílvia Orgué Prof. Antoni Riera Prof. Xavier Verdaguer 《Angewandte Chemie (International ed. in English)》2016,55(28):7988-7992
The MaxPHOX–Ir catalyst system provided the highest selectivity ever reported for the reduction of cyclic enamides derived from α‐ and β‐tetralones. This result indicates that iridium catalysts are also proficient in reducing alkenes bearing metal‐coordinating groups. In the present system, selectivity was pressure‐dependent: In most cases, a decrease in the H2 pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity. 相似文献
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Yao Ge Dr. Zhaobin Han Dr. Zheng Wang Chen‐Guo Feng Qian Zhao Guo‐Qiang Lin Prof. Dr. Kuiling Ding 《Angewandte Chemie (International ed. in English)》2018,57(40):13140-13144
The first asymmetric hydrogenation of 3‐ylidenephthalides has been developed using the IrI complex of a spiro[4,4]‐1,6‐nonadiene‐based phosphine‐oxazoline ligand (SpinPHOX) as the catalyst, affording a wide variety of chiral 3‐substituted phthalides in excellent enantiomeric excesses (up to 98 % ee). The utility of the protocol has been demonstrated in the asymmetric synthesis of chiral drugs NBP and BZP precursor, as well as the natural products chuangxinol and typhaphthalide. 相似文献
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Nan Jiang Pei-Zhi Liu Zhi-Zhou Pan Si-Qing Wang Prof. Dr. Qian Peng Prof. Dr. Liang Yin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(21):e202402195
Chiral trisubstituted vicinal diols are a type of important organic compounds, serving as both common structure units in bioactive natural products and chiral auxiliaries in asymmetric synthesis. Herein, by using siloxypropadienes as the precursors of allyl copper(I) species, a copper(I)-catalyzed diastereoselective and enantioselective reductive allylation of ketones was achieved, providing both syn-diols and anti-diols in good to excellent enantioselectivity. DFT calculations show that cis-γ-siloxy-allyl copper species are generated favorably with either 1-TBSO-propadiene or 1-TIPSO-propadiene. Moreover, the steric difference of TBS group and TIPS group distinguishes the face selectivity of acetophenone, leading to syn-selectivity for 1-TBSO-propadiene and anti-selectivity for 1-TIPSO-propadiene. Easy transformations of the products were performed, demonstrating the synthetic utility of the present method. Moreover, one chiral diol prepared in the above transformations was used as a suitable organocatalyst for the catalytic asymmetric reductive self-coupling of aldimines generated in situ with B2(neo)2. 相似文献
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Ajmal Khan Heng Zhao Meina Zhang Shahid Khan Depeng Zhao 《Angewandte Chemie (International ed. in English)》2020,59(3):1340-1345
Chiral sulfones are of great importance in medicinal chemistry and chemical synthesis. Efficient methods for preparing enantiomerically enriched sulfone‐containing molecules can therefore be of significant value; such methods, however, are uncommon. Herein, we report the first general palladium‐catalyzed sulfonylation of vinyl cyclic carbonates with sodium sulfinates. A series of enantiomerically enriched tertiary allylic sulfones were synthesized in good yields with excellent enantiomeric ratios. Both aliphatic‐ and aryl‐substituted vinyl cyclic carbonates are suitable reactants with excellent results. This reaction features broad substrates scope, readily available starting materials, excellent regio‐ and enantioselectivity, and synthesis of sulfone‐bearing quaternary carbon stereocenters. Through the sulfonylation of geranyl derived cyclic carbonate 1 h , we achieve the formal total synthesis of (+)‐agelasidine A. 相似文献
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Julia Kaufmann Elisabeth Jäckel Dr. Edgar Haak 《Angewandte Chemie (International ed. in English)》2018,57(20):5908-5911
Cascade transformations forming multiple bonds and one‐pot procedures provide rapid access to natural‐product‐like scaffolds from simple precursors. These atom‐economic processes are valuable tools in organic synthesis and drug discovery. Herein, we report on ruthenium‐catalyzed cascade annulations of indole with readily available propargyl alcohols. These provide rapid access to diverse carbazoles, cyclohepta[b]indoles, and further fused polycycles with high selectivity. A bifunctional ruthenium complex featuring a redox‐coupled cyclopentadienone ligand acts as a common catalyst for the different cascade processes. 相似文献
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Gaochao Huang Dr. Zengsheng Yin Prof. Dr. Xingang Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11802-11802