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1.
Richard A. O’BrienArsalan Mirjafari Vijayakumari JajamErin N. Capley Alexandra C. StensonKevin N. West James H. Davis Jr. 《Tetrahedron letters》2011,52(40):5173-5175
The thiol-ene ‘click’ reaction of 1-thioglycerol with ionic liquids incorporating cations bearing appended vinyl- and/or allyl groups is a versatile, single-step means for their conversion into derivatives bearing up to eight hydroxyl groups per cation. 相似文献
2.
Xiaoyong Du Dr. Yanlu Zhang Dr. Dongjie Peng Prof. Dr. Zheng Huang 《Angewandte Chemie (International ed. in English)》2016,55(23):6671-6675
A complementary set of base metal catalysts has been developed for regiodivergent alkene hydrosilylations: iron complexes of phosphine‐iminopyridine are selective for anti‐Markovnikov hydrosilylations (linear/branched up to >99:1), while the cobalt complexes bearing the same type of ligands provide an unprecedented high level of Markovnikov selectivity (branched/linear up to >99:1). Both systems exhibit high efficiency and wide functional group tolerance. 相似文献
3.
Aurapat Ngamnithiporn Toshihiko Iwayama Michael D. Bartberger Brian M. Stoltz 《Chemical science》2020,11(40):11068
The development of a palladium-catalyzed enantioselective decarboxylative allylic alkylation of cyclic siloxyketones to produce enantioenriched silicon-tethered heterocycles is reported. The reaction proceeds smoothly to provide products bearing a quaternary stereocenter in excellent yields (up to 91% yield) with high levels of enantioselectivity (up to 94% ee). We further utilized the unique reactivity of the siloxy functionality to access chiral, highly oxygenated acyclic quaternary building blocks. In addition, we subsequently demonstrated the utility of these compounds through the synthesis of a lactone bearing vicinal quaternary-trisubstituted stereocenters.The development of a palladium-catalyzed enantioselective decarboxylative allylic alkylation of cyclic siloxyketones to produce enantioenriched silicon-tethered heterocycles is reported. 相似文献
4.
A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomerically pure bispiro[benzofuran-oxindole/benzofuran-chromanone]s bearing five consecutive stereocenters including two spiro quaternary carton centers in good yields(up to 93%) with high diastereoselectivities(up to>20:1 dr) and good enantioselectivities(up to>99% ee).Moreover,this is the first example of bifunctional chromone-benzofuranone synthon directed organocatalytic tandem reaction,and also the first example of the bispiro[benzofuran-oxindole] and bispirobenzofuranone,potentially useful in medicinal chemistry. 相似文献
5.
One‐Pot Organocatalytic Enantioselective Michael/Povarov Domino Strategy for the Construction of Spirooctahydroacridine‐3,3′‐oxindole Scaffolds
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An asymmetric organocatalytic one‐pot strategy for the construction of spirooctahydroacridine‐3,3′‐oxindole scaffolds has been successfully developed by means of a domino Michael/Povarov reaction sequence. The one‐pot protocol affords the chiral spirocyclohexaneoxindoles bearing an octahydroacridine motif with five stereocenters in good to high yields (up to 89 % yield) with excellent to perfect diastereoselectivities (up to >20:1 d.r.) and enantioselectivities (up to >99 % ee). This highly efficient one‐pot domino procedure will allow diversity‐oriented syntheses of this intriguing class of compounds with potential biological activities. 相似文献
6.
Kunihiro Ichimura Sang-Keun Oh Masanori Fujimaki Yoko Matsuzawa Masaru Nakagawa 《Journal of inclusion phenomena and macrocyclic chemistry》1999,35(1-2):173-183
Crown conformers of O-carboxymethylated calix[4]resorcinarenes (CRA-CMs) bearing four perfluorooctyl- and octylazobenzene residues at the lower rim of the cyclic skeleton were synthesized to investigate the resistance to desorption of CRA-CMs forming self-assembled monolayers on aminosilylated silica substrates and the surface energy photocontrol based on E- to-Z photoisomerization of the azobenzene moiety. In comparison with CRA-CM monolayers on silica substrates, the desorption of CRA-CMs on the aminated substrate was remarkably suppressed even when CRA-CM monolayers were sonicated in polar solvents and even in water. The high desorption-resistance was attributable to multi-point adsorption of CRA-CMs through COOH/NH2 interactions. UV-Vis spectral studies revealed that CRA-CM substituted with p-octylazobenzene exhibited high E- to-Z photoisomerizability up to 92% in self-assembled monolayers, while less photoisomerizability was observed for CRA-CM bearing p-perfluorooctylazobenzenes due to the steric hindrance of the larger perfluoroalkyl chains. Photoinduced changes of contact angles for water up to 8.3° were observed for a CRA-CM monolayer. 相似文献
7.
Dual Catalysis for the Redox Annulation of Nitroalkynes with Indoles: Enantioselective Construction of Indolin‐3‐ones Bearing Quaternary Stereocenters
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Dr. Ren‐Rong Liu Shi‐Chun Ye Dr. Chuan‐Jun Lu Dr. Gui‐Lin Zhuang Prof. Dr. Jian‐Rong Gao Prof. Dr. Yi‐Xia Jia 《Angewandte Chemie (International ed. in English)》2015,54(38):11205-11208
The enantioselective redox annulation of nitroalkynes with indoles is enabled by gold/chiral phosphoric acid dual catalysis. A range of indolin‐3‐one derivatives bearing quaternary stereocenters at the C2 position were afforded in good yields and excellent enantioselectivities (up to 96 % ee) from readily available starting materials. 相似文献
8.
Abdul Raheem Keeri Dr. Andrea Gualandi Prof. Dr. Andrea Mazzanti Prof. Dr. Janusz Lewinski Prof. Dr. Pier Giorgio Cozzi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18949-18952
The first catalytic asymmetric addition of TosMIC to unactivated ketones is presented. A combination of Me2Zn and aminoalcohol catalyst promoted the aldol addition/cyclization reaction to render oxazolines possessing a fully substituted stereocenter with excellent yields (up to 92 %), high enantioselectivities (up to 96 %), and complete diastereoselectivity. The chiral oxazolines were then used to give, after a straightforward acid hydrolysis, enantioenriched building blocks bearing tertiary alcohol motifs such as hydroxylaldehydes, hydroxylacids, and hydroxylesters without racemization. 相似文献
9.
《Mendeleev Communications》2023,33(3):331-333
A three-component protocol was adopted to efficiently prepare new bis(pyrazolo[1,5-a]pyrimidines) linked to different spacers in 80-92% yields from 1H-pyrazole-3,5-diamines, malononitrile and bis(aldehydes). The p-xylene-linked bis(pyrimidine) bearing 3-positioned 4-methoxy-benzyl substituent had the best antibacterial activity with MIC / MBC values up to 2.2 / 4.4 µm. 相似文献
10.
Yuxuan Liu Wang Miao Prof. Weijun Tang Prof. Dong Xue Prof. Jianliang Xiao Prof. Chao Wang Prof. Changzhi Li 《化学:亚洲杂志》2021,16(13):1725-1729
A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h−1, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity. 相似文献
11.
Mingxu Li Jian Zhang Yashi Zou Fengfan Zhou Zhenfeng Zhang Wanbin Zhang 《Chemical science》2021,12(45):15061
Asymmetric hydrogenation of unsaturated morpholines has been developed by using a bisphosphine-rhodium catalyst bearing a large bite angle. With this approach, a variety of 2-substituted chiral morpholines could be obtained in quantitative yields and with excellent enantioselectivities (up to 99% ee). The hydrogenated products could be transformed into key intermediates for bioactive compounds.2-Substituted chiral morpholines were synthesized via a newly developed asymmetric hydrogenation of dehydromorpholines catalyzed by a bisphosphine–rhodium complex bearing a large bite angle. 相似文献
12.
Dr. Ren-Rong Liu Yong-Gang Wang Ying-Long Li Bing-Bing Huang Dr. Ren-Xiao Liang Prof. Dr. Yi-Xia Jia 《Angewandte Chemie (International ed. in English)》2017,56(26):7475-7478
Palladium-catalyzed enantioselective dearomative arylalkynylation of N-substituted indoles, through a Heck/Sonogashira sequence, was established using a new BINOL-based phosphoramidite as the chiral ligand. A wide range of 2,3-disubstituted indolines, bearing vicinal quaternary and tertiary stereocenters, were efficiently constructed in one step with excellent enantioselectivities (up to 97 % ee) and diastereoselectivities (>20:1). 相似文献
13.
Vincent Terrasson Dr. Renata Marcia de Figueiredo Dr. Jean Marc Campagne Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(26):7875-7880
An enantioselective cyclopropanation of α‐substituted α,β‐unsaturated aldehydes with bromomalonate has been successfully developed through a domino Michael/α‐alkylation strategy. The method allows the efficient formation of cyclopropanes bearing a quaternary carbon stereocenter at the α‐position of the aldehydes by using iminium/enamine catalysis and gives a nice extension on the organocatalytic cyclopropanation of bromomalonate and α,β‐unsaturated aldehydes previously reported by other groups. Very good yields (up to 81 %) and enantioselectivities (up to 97 % ee) have been obtained. The optically active cyclopropane derivatives are of high synthetic interest as useful targets for further elaboration into more complex structures. 相似文献
14.
Organocatalytic Domino Oxa‐Michael/1,6‐Addition Reactions: Asymmetric Synthesis of Chromans Bearing Oxindole Scaffolds
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Kun Zhao Dr. Ying Zhi Tao Shu Dr. Arto Valkonen Prof. Dr. Kari Rissanen Prof. Dr. Dieter Enders 《Angewandte Chemie (International ed. in English)》2016,55(39):12104-12108
An asymmetric organocatalytic domino oxa‐Michael/1,6‐addition reaction of ortho‐hydroxyphenyl‐substituted para‐quinone methides and isatin‐derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4‐phenyl‐substituted chromans bearing spiro‐connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee). 相似文献
15.
June Izquierdo Noémie Demurget Dr. Aitor Landa Prof. Tore Brinck Prof. Jose M. Mercero Prof. Peter Dinér Prof. Mikel Oiarbide Prof. Claudio Palomo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12431-12438
A bifunctional amine/squaramide catalyst promoted direct aldol addition of an hydantoin surrogate to pyridine 2-carbaldehyde N-oxides to afford adducts bearing two vicinal tertiary/quaternary carbons in high diastereo- and enantioselectivity (d.r. up to >20:1; ee up to 98 %) is reported. Acid hydrolysis of adducts followed by reduction of the N-oxide group yields enantiopure carbinol-tethered quaternary hydantoin-azaarene conjugates with densely functionalized skeletons. DFT studies of the potential energy surface (B3LYP/6–31+G(d)+CPCM (dichloromethane)) of the reaction correlate the activity of different catalysts and support an intramolecular hydrogen-bond-assisted activation of the squaramide moiety in the transition state of the catalytic reaction. 相似文献
16.
Robert T. Shaver Djordje Vlaovic Ilya Reviakine Rhonda Wittaker Lorenzo P. Ferrari Harald D. H. Stver 《Journal of polymer science. Part A, Polymer chemistry》1995,33(6):957-965
A range of new functional copolymers bearing aldehyde and carboxylic acid groups have been prepared by functionalization of poly(4-methylstyrene). These polymers have molecular weights from 2,000 to 16,500 and contain up to 20% aldehyde and up to 90% carboxylic acid groups. The reaction proceeds by selective catalytic oxidations with molecular oxygen or air in acetic acid/organic cosolvent mixtures in presence of cobalt acetate and sodium bromide or hydrogen bromide. The effects of reaction temperature, catalyst, co-solvents and oxygen partial pressure on the reaction are described. © 1995 John Wiley & Sons, Inc. 相似文献
17.
We report an enantioselective desymmetrization of cyclopropenes by intermolecular Rh-catalyzed hydroacylation. Cyclopropylketones, bearing quaternary stereocenters, are produced with diastereocontrol (up to >20:1) and excellent enantiomeric excess (up to >99 ee). 相似文献
18.
Salen-chromium(III) complexes bearing sterically demanding substituents at the 3 and 3′ positions are applied for the oxo-Diels-Alder reaction of various aldehydes with Danishefsky’s diene. The readily-accessible complex bearing a bulky 3-phenylpent-3-yl substituent revealed its potential affording the cycloadducts with improved reactivity and excellent selectivities up to 96% ee, being considerably superior to the classic Jacobsen’s catalyst. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7583-7586
Palladium‐catalyzed enantioselective dearomative arylalkynylation of N‐substituted indoles, through a Heck/Sonogashira sequence, was established using a new BINOL‐based phosphoramidite as the chiral ligand. A wide range of 2,3‐disubstituted indolines, bearing vicinal quaternary and tertiary stereocenters, were efficiently constructed in one step with excellent enantioselectivities (up to 97 % ee) and diastereoselectivities (>20:1). 相似文献
20.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(52):16858-16862
The traceless Petasis borono‐Mannich reaction of enals, sulfonylhydrazines, and allylboronates, catalyzed by chiral biphenols, results in an asymmetric reductive transposition of the in situ generated allylic diazene. Acyclic 1,4‐diene products bearing either alkyl‐ or aryl‐substituted benzylic stereocenters are afforded in excellent yields and enantiomeric ratios of up to 99:1. The use of crotylboronates in the reaction results in concomitant formation of two stereocenters in either a 1,4‐syn or anti relationship from the corresponding E ‐ or Z ‐crotylboronate used in the reaction. The use of β‐monosubstituted enals in the asymmetric traceless Petasis borono‐Mannich reaction of crotylboronates installs tertiary methyl‐bearing stereocenters in good yields and high enantioselectivities. 相似文献