- Synthesis and structure-property relationships of polypropylene-g- poly(ethylene-co-1-butene) graft copolymers with well-defined long chain branched molecular structures
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A series of polypropylene-g-poly(ethylene-co-1-butene) (PP-g-EBR) graft copolymers with well-defined long chain branched (LCB) molecular structures were synthesized via the combination of coordination polymerization and anionic polymerization. The structu
- Wang, Lu,Wan, Dong,Zhang, Zhenjiang,Liu, Feng,Xing, Haiping,Wang, Yanhui,Tang, Tao
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- Access to Trisubstituted Fluoroalkenes by Ruthenium-Catalyzed Cross-Metathesis
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Although the olefin metathesis reaction is a well-known and powerful strategy to get alkenes, this reaction remained highly challenging with fluororalkenes, especially the Cross-Metathesis (CM) process. Our thought was to find an easy accessible, convenient, reactive and post-functionalizable source of fluoroalkene, that we found as the methyl 2-fluoroacrylate. We reported herein the efficient ruthenium-catalyzed CM reaction of various terminal and internal alkenes with methyl 2-fluoroacrylate giving access, for the first time, to trisubstituted fluoroalkenes stereoselectively. Unprecedent TON for CM involving fluoroalkene, up to 175, have been obtained and the reaction proved to be tolerant and effective with a large range of olefin partners giving fair to high yields in metathesis products. (Figure presented.).
- Nouaille, Augustin,Pannecoucke, Xavier,Poisson, Thomas,Couve-Bonnaire, Samuel
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p. 2140 - 2147
(2021/03/06)
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- Pd-catalyzed C4-Dearomative Allylation of Benzyl Ammoniums with Allyltributylstannane
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A dearomative C4-allylation of benzyl ammoniums with allyltributylstannane by a palladium catalysis is described. A triarylphosphine-ligated palladium catalyst, which is capable of cleaving benzylic CN bonds, realized facile dearomative reactions with C4 selectivity. Combined with precedented C2- A nd C3-selective functionalizations of benzyl amine derivatives, the present reaction can provide a new synthetic option for the synthesis of multi-substituted alicyclic compounds as well as aromatic compounds.
- Kayashima, Yuki,Komatsuda, Masaaki,Muto, Kei,Yamaguchi, Junichiro
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supporting information
p. 836 - 839
(2020/07/23)
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- Efficient preparation method of 1-aryl-4-butene compound
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The invention belongs to the technical field of fine chemicals and related chemistry, and provides an efficient preparation method of a 1-aryl-4-butene compound. The 1-aryl-4-butene compound can be obtained by taking halogen-containing methyl aromatic hyd
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Paragraph 0047-0050
(2020/05/30)
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- Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis
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We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.
- Meng, Qing-Yuan,Schirmer, Tobias E.,Katou, Kousuke,K?nig, Burkhard
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supporting information
p. 5723 - 5728
(2019/04/03)
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- Umpolung of Carbonyl Groups as Alkyl Organometallic Reagent Surrogates for Palladium-Catalyzed Allylic Alkylation
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Palladium-catalyzed allylic alkylation of nonstabilized carbon nucleophiles is difficult and remains a major challenge. Reported here is a highly chemo- and regioselective direct palladium-catalyzed C-allylation of hydrazones, generated from carbonyls, as a source of umpolung unstabilized alkyl carbanions and surrogates of alkyl organometallic reagents. Contrary to classical allylation techniques, this umpolung reaction utilizes hydrazones prepared not only from aryl aldehydes but also from alkyl aldehydes and ketones as renewable feedstocks. This strategy complements the palladium-catalyzed coupling of unstabilized nucleophiles with allylic electrophiles by providing an efficient and selective catalytic alternative to the traditional use of highly reactive alkyl organometallic reagents.
- Zhu, Dianhu,Lv, Leiyang,Li, Chen-Chen,Ung, Sosthene,Gao, Jian,Li, Chao-Jun
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supporting information
p. 16520 - 16524
(2018/11/23)
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- 2,6-DIOXO,-2,3-DIHYDRO-1H-PURINE COMPOUNDS USEFUL FOR TREATING DISORDERS RELATED TO THE ACTIVITY OF THE TRPA1 CHANNEL
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Compounds of formula (VIII) and compositions for treating disorders related to TRPA1 are described herein.
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- Harnessing Alkyl Amines as Electrophiles for Nickel-Catalyzed Cross Couplings via C-N Bond Activation
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We developed a strategy to harness alkyl amines as alkylating agents via C-N bond activation. This Suzuki-Miyaura cross coupling of alkylpyridinium salts, readily formed from primary amines, is the first example of a metal-catalyzed cross coupling via C-N bond activation of an amine with an unactivated alkyl group. This reaction enjoys broad scope and functional group tolerance. Primary and secondary alkyl groups can be installed. Preliminary studies suggest a NiI/NiIII catalytic cycle.
- Basch, Corey H.,Liao, Jennie,Xu, Jianyu,Piane, Jacob J.,Watson, Mary P.
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supporting information
p. 5313 - 5316
(2017/04/27)
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- Monocarboxylation and intramolecular coupling of butenylated arenes via palladium-catalyzed C-H activation process
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A novel and practical reaction for the direct intramolecular oxidative coupling of butenylated arenes is reported. With the catalysis of Pd(OAc)2, reactions of various butenylated arenes and carboxylic acids with Selectfluor reagent in CH3CN solution afforded the corresponding monocarboxylation/cyclization products in good yields under mild conditions. This research demonstrated an economic method with the synthesis of 2-tetralyl carboxylic esters, a valuable class of bioactive compounds.
- Liu, Rui,Lu, Ze-Hai,Hu, Xiao-Hui,Li, Jun-Li,Yang, Xian-Jin
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supporting information
p. 1489 - 1492
(2015/03/30)
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- Chromium aryl complexes with N-donor ligands as catalyst precursors for selective ethylene trimerization
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A series of 8-amino-2-arylquinoline ligands (1-6) were synthesized and reacted with CH3CrCl2(thf)3. Under these conditions a CH bond of the 2-aryl substituent is metalated, leading to organochromium complexes with monoanionic tridentate ligands (8-13). The presence of a chromium-carbon σ bond in these complexes has been established by X-ray analysis. Furthermore, 8-(piperidin-1-yl)quinoline (14) was used as neutral bidentate ligand in addition to an external aryl group, leading to complex 15. Finally, the tris-aryl complex 18 was synthesized, which features a rare five-coordinate chromium(III) metal center. All chromium complexes were tested as catalysts for the selective trimerization of ethylene after activation with methylaluminoxane (MAO). Several of the new catalyst precursors show good behavior for the selective trimerization of ethylene. Although chlorido ligands in the catalyst precursor will be substituted by methyl groups during the activation with MAO, there is a clear difference in the catalytic behavior when the complex contains a methyl (or aryl) group prior to addition of MAO. The mechanism of catalyst activation has been studied in more detail with the tris-aryl complex 18.
- Ronellenfitsch, Mathias,Wadepohl, Hubert,Enders, Markus
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supporting information
p. 5758 - 5766
(2015/02/19)
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- Wacker-type oxidation and dehydrogenation of terminal olefins using molecular oxygen as the sole oxidant without adding ligand
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An efficient and economical palladium-catalyzed oxidation system has been identified. The oxidation system, characterized by not adding ligand and using molecular oxygen as the sole oxidant, can realize the Tsuji-Wacker oxidation of terminal olefins and especially styrenes to methyl ketones; in addition, this system can achieve tandem Wacker oxidation-dehydrogenation of terminal olefins to α,β-unsaturated ketones.
- Wang, Yu-Fei,Gao, Ya-Ru,Mao, Shuai,Zhang, Yan-Lei,Guo, Dong-Dong,Yan, Zhao-Lei,Guo, Shi-Huan,Wang, Yong-Qiang
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supporting information
p. 1610 - 1613
(2014/04/17)
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- Dual role of allylsamarium bromide as a Grignard reagent and a single electron transfer reagent in the one-pot synthesis of terminal olefins
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The utility of allylsamarium bromide, both as a nucleophilic reagent and a single-electron transfer reagent, in the reaction of carbonyl compounds with allylsamarium bromide in the presence of diethyl phosphate is reported in this communication. From a synthetic point of view, a simple one-pot method for the preparation of terminal olefins is developed.
- Li, Ying,Hu, Yuan-Yuan,Zhang, Song-Lin
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supporting information
p. 10635 - 10637
(2013/11/06)
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- Dinuclear iron complex-catalyzed cross-coupling of primary alkyl fluorides with aryl grignard reagents
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Iron-catalyzed cross-coupling of nonactivated primary alkyl fluorides with aryl Grignard reagents has been achieved by using the low-coordinate dinuclear iron complex [(IPr2Me2)Fe(μ2-NDipp) 2Fe(IPr2Me2)] as the catalyst. This iron-catalyzed C(sp3)-F bond arylation reaction is applicable to a variety of aryl Grignard reagents and primary alkyl fluorides. The product pattern suggests the involvement of a radical-type mechanism for its C-F bond scission step.
- Mo, Zhenbo,Zhang, Qiang,Deng, Liang
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p. 6518 - 6521
(2012/10/29)
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- Picosecond radical kinetics. Rate constants for ring openings of 2-aryl-substituted cyclopropylcarbinyl radicals
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The kinetics of ring openings of a series of eight (trans-2-arylcyclopropyl)methyl radicals (1) were studied by indirect kinetic methods using Barton's PTOC esters as radical precursors and reaction with PhSeH as the competition reaction. The substituents were CF3, F, Me, and OMe located on both the para and meta positions of the aromatic ring. Syntheses of the radical precursors and the products of the radical reactions are described. Kinetics were determined between -43 and 25°C in four cases (CF3 and OMe substituents) and at 0 and 25°C in the other four cases. The rate constants at 25°C ranged from 1.0 x 1011 s-1 (p-CH3) to 4.1 x 1011 s-1 (p-CF3). The relatively large acceleration of the p-CF3 group, ca. 2.5 times as fast as the parent system with Ar = Ph, correlates well with Adam's ΔD substituent parameters but not with other radical substituent parameters. These calibrated radical rearrangements provide a new set of ultrafast reactions that can be applied in mechanistic probe studies.
- Newcomb,Choi,Toy
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p. 1123 - 1135
(2007/10/03)
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- Selective Cross Coupling via Oxovanadium(V)-Induced Oxidative Desilylation of Benzylic Silanes
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Benzylic silanes bearing an electron-donating group at the ortho- or para-position underwent the oxovanadium(V)-induced one-electron oxidative desilylation due to low ionization potential, which was applied to the intermolecular regioselective coupling with allylic silanes or silyl enol ether.
- Hirao, Toshikazu,Fujii, Takashi,Ohshiro, Yoshiki
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p. 8005 - 8008
(2007/10/02)
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- Structure of ω-Arylalkyl Radicals: A 13C CIDNP Investigation
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Thermolysis of a series of ω-arylalkanoyl m-chlorobenzoyl (and acetyl) peroxides at ca. 100 deg C in cyclohexanone and in hexachloroacetone was studied by using 13C chemically induced dynamic nuclear polarization.Analysis of the observed 13C polarizations indicate that all the three radicals (β-arylethyl, γ-arylpropyl and δ-arylbutyl) have open-chain structures with no evidence for aryl participation resulting in spirocycloalkylcyclohexadienyl radicals.
- Olah, George A.,Krishnamurthy, V. V.,Singh, Brij P.,Iyer, Pradeep S.
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p. 955 - 963
(2007/10/02)
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- COMPLEXES OF TRANSITION METALS IN THE CHEMISTRY OF CONJUGATED SYSTEMS. III. REACTION OF DIENE HYDROCARBONS WITH ORGANOMAGNESIUM COMPOUNDS IN THE PRESENCE OF SALTS AND COMPLEXES OF TRANSITION METALS
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The effect of the structure of the reagents and the nature of the catalyst on the direction and selectivity in the reaction of 1,3-dienes and their derivatives with aromatic Grignard reagents was investigated.It was shown that in the presence of salts and complexes of iron(III) 1,3-alkadienes R1CH=C(R2)C(R3)=CH2 react with arylmagnesium halides to form trans-(E)-1-aryl-1,3-alkadienes, whereas the sterically hindered (R2, R3=CH3) cyclic 1,3-alkadienes and also 1,2-alkadienes give mainly adducts (1:1).Catalysis by the phosphine complexes of nickel(II) leads to the formation of telomeric (2:1) (E)-1-aryl-2,7- and (E,E)-1-aryl-2,6-alkadienes.The results demonstrate the determining role of the stereochemical conditions for the coordination of the diene in the course of the reaction and also the significant contribution from the processes of one-electron reduction of the catalyst.
- Zubritskii, L. M.,Romashchenkova, N. D.,Petrov, A. A.
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p. 2157 - 2167
(2007/10/02)
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