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1.
Chiral amino thioacetate ligands were prepared from the corresponding amino alcohols and used as catalysts for enantioselective aryl transfer reaction. The amino thioacetates were remarkably superior to the corresponding amino alcohols. Low catalyst loadings of only 1-2.5 mol % were sufficient to achieve excellent enantioselectivity as well as high conversion in short reaction time. The results reveal that the thioacetoxy moiety of the amino thioacetates has a surprisingly beneficial effect in enhancing the asymmetric induction. 相似文献
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A series of new planar and central chiral ligands based on [2.2]paracyclophane backbones were designed and prepared from enantiomerically pure 4-amino-13-bromo[2.2]paracyclophane and commercially available chiral amino alcohols. Their application in a copper-catalyzed asymmetric Henry reaction resulted in secondary alcohols with high yield and excellent selectivity for active aldehydes (up to 94% ee). This is a successful example of employing planar chiral [2.2]paracyclophane ligands in copper-catalyzed reaction. 相似文献
3.
Mei-Ling Han Xiang-Ping Hu Jia-Di HuangLi-Gong Chen Zhuo Zheng 《Tetrahedron: Asymmetry》2011,22(2):222-225
A series of chiral amino alcohols have been prepared from cheap and readily available (S)-1-phenylethylamine through a one-step transformation. The ability of these newly developed amino alcohols as chiral ligands was evaluated in the Ru-catalyzed asymmetric transfer hydrogenation of aromatic alkyl ketones, providing chiral secondary alcohols with good to excellent conversions (71-100%) and moderate to good enantioselectivities (67-95% ee). The results also showed that the structure of these amino alcohols has a significant influence on the conversion and enantioselectivity. 相似文献
4.
Multicomponent Synthesis of Chiral Bidentate Unsymmetrical Unsaturated N‐Heterocyclic Carbenes: Copper‐Catalyzed Asymmetric CC Bond Formation 下载免费PDF全文
Dr. Claire Jahier‐Diallo Dr. Marie S. T. Morin Dr. Pierre Queval Dr. Mathieu Rouen Isabelle Artur Pierre Querard Dr. Loic Toupet Dr. Christophe Crévisy Dr. Olivier Baslé Dr. Marc Mauduit 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):993-997
A multicomponent strategy was applied to the synthesis of chiral bidentate unsaturated hydroxyalkyl‐ and carboxyalkyl‐N‐heterocyclic carbene (NHC) precursors. The newly developed low‐cost chiral ligands derived from amino alcohols and amino acids were evaluated in copper‐catalyzed asymmetric conjugated addition and asymmetric allylic alkylation, which afforded the desired tertiary and quaternary carbon stereocenters with excellent regio‐ and enantioselectivities (up to 99:1 e.r.). 相似文献
5.
Tao Xu Chao Liang Yan Cai Jian Li Ya-Min Li Xin-Ping Hui 《Tetrahedron: Asymmetry》2009,20(23):2733-2736
Three chiral β-hydroxy amide ligands were prepared by the reaction of benzyl chloride with amino alcohols derived from l-tyrosine. The titanium(IV) complex of chiral ligand 4a was found to be an effective catalyst for the asymmetric addition of methyl propiolate to aliphatic and aromatic aldehydes. The γ-hydroxy-α,β-acetylenic esters were obtained in excellent enantiomeric excesses (up to 94% ee) under optimized conditions. 相似文献
6.
Shang G Liu D Allen SE Yang Q Zhang X 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(27):7780-7784
Two beta-receptor agonists (-)-denopamine and (-)-arbutamine were prepared in good yields and enantioselectivities by asymmetric hydrogenation of unprotected amino ketones for the first time by using Rh catalysts bearing electron-donating phosphine ligands. A series of alpha-primary and secondary amino ketones were synthesized and hydrogenated to produce various 1,2-amino alcohols in good yields and with good enantioselectivies. This Rh electron-donating phosphine-catalyzed asymmetric hyderogenation represents one of the most promising and convenient approaches towards the asymmetric synthesis of chiral amino alcohols. 相似文献
7.
Petra DG Kamer PC Spek AL Schoemaker HE van Leeuwen PW 《The Journal of organic chemistry》2000,65(10):3010-3017
A new class of efficient catalysts was developed for the asymmetric transfer hydrogenation of unsymmetrical ketones. A series of chiral N,S-chelates (6-22) was synthesized to serve as ligands in the iridium(I)-catalyzed reduction of ketones. Both formic acid and 2-propanol proved to be suitable as hydrogen donors. Sulfoxidation of an (R)-cysteine-based aminosulfide provided a diastereomeric ligand family containing a chiral sulfur atom. The two chiral centers of these ligands showed a clear effect of chiral cooperativity. In addition, aminosulfides containing two asymmetric carbon atoms in the backbone were synthesized. Both the sulfoxide-containing beta-amino alcohols and the aminosulfides derived from 1,2-disubstituted amino alcohols gave rise to high reaction rates and moderate to excellent enantioselectivities in the reduction of various ketones. The enantioselective outcome of the reaction was favorably affected by selecting the most appropriate hydrogen donor. Enantioselectivities of up to 97% were reached in the reduction of aryl-alkyl ketones. 相似文献
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A palladium-catalyzed asymmetric allylation of isatins with allylic alcohols as an allyl donor was developed by using chiral spiro phosphoramidite ligands. A variety of chiral tertiary homoallylic alcohols 3-allyl-3-hydroxy-2-oxindoles were prepared directly from allylic alcohols in one step with excellent yields and moderate enantioselectivities. This represents the first catalytic asymmetric allylation of ketones with allylic alcohol as the allylating agent. 相似文献
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The review analyzes methods for the synthesis of amino alcohols containing cage-like norbornene, norbornane, and adamantane fragments. Such reactions of amino alcohols as selective functionalization of hydroxy and amino groups, as well as heterocyclizations with formation of nitrogen- and oxygen-containing heterocycles, are considered. Biological activity of cage-like amino alcohols and their derivatives and their use as ligands in catalytic asymmetric syntheses are discussed. 相似文献
12.
《中国化学》2018,36(9):851-856
A series of novel and easily accessed ferrocene‐based amino‐phosphine‐sulfonamide (f‐Amphamide) ligands have been developed and applied in Ir‐catalyzed asymmetric hydrogenation of aryl ketones, affording the corresponding chiral secondary alcohols with excellent results (up to >99% conversion, >99% ee and TON up to 200 000). DFT calculations suggest an activating model involving an alkali cation Li+. 相似文献
13.
《Tetrahedron: Asymmetry》2001,12(15):2147-2152
A series of binaphthyl-derived amino alcohols were synthesized and used as catalytic ligands in the asymmetric alkynylation of aromatic aldehydes in the presence of a dialkylzinc reagent. The alkynylation of a variety of aromatic aldehydes gave the corresponding chiral propargylic alcohols in 61–93% e.e. 相似文献
14.
《Tetrahedron: Asymmetry》1998,9(19):3461-3490
A series of new chiral sulfur–nitrogen chelate ligands, derived from amino acids, has been synthesised rationally. Fruitless experiments into catalytic asymmetric conjugate additions and desymmetrisation of meso-epoxides led us to analyse our ligands in the catalytic asymmetric addition of diethylzinc to aromatic aldehydes. These latter experiments were successful with chiral benzylic alcohols being obtained in up to 82% enantiomeric excess. 相似文献
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16.
Mohammad Shahidul Islam Abdullah Saleh Alammari Assem Barakat Saeed Alshahrani Matti Haukka Abdullah Mohammed Al-Majid 《Molecules (Basel, Switzerland)》2021,26(23)
Five new C2-symmetric chiral ligands of 2,5-bis(imidazolinyl)thiophene (L1–L3) and 2,5-bis(oxazolinyl)thiophene (L4 and L5) were synthesized from thiophene-2,5-dicarboxylic acid (1) with enantiopure amino alcohols (4a–c) in excellent optical purity and chemical yield. The utility of these new chiral ligands for Friedel–Crafts asymmetric alkylation was explored. Subsequently, the optimized tridentate ligand L5 and Cu(OTf)2 catalyst (15 mol%) in toluene for 48 h promoted Friedel–Crafts asymmetric alkylation in moderate to good yields (up to 76%) and with good enantioselectivity (up to 81% ee). The bis(oxazolinyl)thiophene ligands were more potent than bis(imidazolinyl)thiophene analogues for the asymmetric induction of the Friedel–Crafts asymmetric alkylation. 相似文献
17.
《Tetrahedron: Asymmetry》2003,14(16):2453-2458
A new approach has been evaluated for the preparation of solution free and polymer supported chiral bicyclic amino alcohols. This strategy involves the use of readily available starting materials and allows chiral ligands characterised by the bispidine core, bearing a stereogenic centre β to one of the nitrogen atoms to be obtained. The first results obtained from the application of these ligands in the asymmetric addition reaction of diethylzinc to benzaldehyde are discussed. 相似文献
18.
Rhodium‐catalyzed Asymmetric Hydrogenation of α‐Dehydroamino Ketones: A General Approach to Chiral α‐amino Ketones 下载免费PDF全文
Rhodium/DuanPhos‐catalyzed asymmetric hydrogenation of aliphatic α‐dehydroamino ketones has been achieved and afforded chiral α‐amino ketones in high yields and excellent enantioselectives (up to 99 % ee), which could be reduced further to chiral β‐amino alcohols by LiAlH(tBuO)3 with good yields. This protocol provides a readily accessible route for the synthesis of chiral α‐amino ketones and chiral β‐amino alcohols. 相似文献
19.
Nermin Meriç Cezmi Kayan Nevin Gürbüz Mehmet Karakaplan Nil Ertekin Binbay Murat Aydemir 《Tetrahedron: Asymmetry》2017,28(12):1739-1749
Metal-catalyzed asymmetric transfer hydrogenation is a powerful and practical method for the reduction of ketones to produce the corresponding secondary alcohols, which are valuable building blocks in the pharmaceutical, perfume, and agrochemical industries. Hence, a series of novel chiral β-amino alcohols were synthesized by chiral amines with regioselective ring opening of (S)-propylene oxide or reaction with (S)-(+)-2-hydroxypropyl p-toluenesulfonate by a straightforward method. The chiral ruthenium catalytic systems generated from [Ru(arene)(μ-Cl)Cl]2 complexes and chiral phosphinite ligands based on amino alcohol derivatives were employed in asymmetric transfer hydrogenation of ketones to give the corresponding optically active alcohols; (2S)-1-{[(2S)-2-[(diphenylphosphanyl)oxy]propyl][(1R)-1-phenylethyl]amino}propan-2-yldiphenylphosphinitobis[dichol-oro(η6-benzene)ruthenium(II)] acts an excellent catalyst in the reduction of α-naphthyl methyl ketone, giving the corresponding alcohol with up to 99% ee. The substituents on the backbone of the ligands were found to have a remarkable effect on both the conversion and enantioselectivity of the catalysts. Furthermore, this transfer hydrogenation is characterized by low reversibility under these conditions. 相似文献
20.
A highly efficient nickel-catalyzed asymmetric alkylative coupling of alkynes, aldehydes, and dimethylzinc has been realized by using bulky spirobiindane phosphoramidite ligands, affording allylic alcohols with a tetrasubstituted olefin functionality in high yields, high regioselectivities, and excellent enantioselectivities. 相似文献