- Photoinduced Hydroarylation and Cyclization of Alkenes with Luminescent Platinum(II) Complexes
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Photoinduced hydroarylation of alkenes is an appealing synthetic strategy for arene functionalization. Herein, we demonstrated that aryl radicals generated from electron-deficient aryl chlorides/bromides could be trapped by an array of terminal/internal aryl alkenes in the presence of [Pt(O^N^C^N)] under visible-light (410 nm) irradiation, affording anti-Markovnikov hydroarylated compounds in up to 95 % yield. Besides, a protocol for [Pt(O^N^C^N)]-catalyzed intramolecular photocyclization of acrylanilides to give structurally diverse 3,4-dihydroquinolinones has been developed.
- Cheng, Hanchao,Lam, Tsz-Lung,Liu, Yungen,Tang, Zhou,Che, Chi-Ming
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supporting information
p. 1383 - 1389
(2020/11/30)
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- 1,3-Difunctionalization of β-alkyl nitroalkenes via combination of Lewis base catalysis and radical oxidation
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Upon treatment with a Lewis base catalyst, β-alkyl-substituted nitroalkenes could be readily converted into allylic nitro compounds. Examples of either C-1 or C-3 functionalization methods have been reported through nitro-elimination, giving alkene products. In this work, successful 1,3-difunctionalization was achieved through a synergetic Lewis base catalysis and TBHP radical oxidation, giving vinylic alkoxyamines in good to excellent yields. This work further extended the general synthetic application of β-alkyl nitroalkenes.
- Wang, Ye,Zheng, Lei,Shi, Xiaodong,Chen, Yunfeng
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supporting information
p. 886 - 889
(2021/02/01)
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- Visible-Light-Induced Meerwein Fluoroarylation of Styrenes
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An unprecedented approach for assembling a broad range of 1,2-diarylethane derivatives with fluorine-containing fully substituted carbon centers was developed. The protocol features straightforward operation, proceeds under metal-free condition, and accommodates a large variety of synthetically useful functionalities. The critical aspect to the success of this novel transformation lies in using aryldiazonium salts as both aryl radical progenitor and also as single electron acceptor which elegantly enables a radical-polar crossover manifold.
- Tang, Hai-Jun,Zhang, Bin,Xue, Fei,Feng, Chao
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supporting information
p. 4040 - 4044
(2021/05/26)
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- Palladium-Catalyzed Markovnikov Hydroaminocarbonylation of 1,1-Disubstituted and 1,1,2-Trisubstituted Alkenes for Formation of Amides with Quaternary Carbon
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Hydroaminocarbonylation of alkenes is one of the most promising yet challenging methods for the synthesis of amides. Herein, we reported the development of a novel and effective Pd-catalyzed Markovnikov hydroaminocarbonylation of 1,1-disubstituted or 1,1,2-trisubstituted alkenes with aniline hydrochloride salts to afford amides bearing an α quaternary carbon. The reaction makes use of readily available starting materials, tolerates a wide range of functional groups, and provides a facile and straightforward approach to a diverse array of amides bearing an α quaternary carbon. Mechanistic investigations suggested that the reaction proceeded through a palladium hydride pathway. The hydropalladation and CO insertion are reversible, and the aminolysis is probably the rate-limiting step.
- Yang, Hui-Yi,Yao, Ya-Hong,Chen, Ming,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 7298 - 7305
(2021/05/26)
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- Ni-Catalyzed Reductive Allylation of α-Chloroboronates to Access Homoallylic Boronates
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The transition-metal-catalyzed allylation reaction is an efficient strategy for the construction of new carbon-carbon bonds alongside allyl or homoallylic functionalization. Herein we describe a Ni-catalyzed reductive allylation of α-chloroboronates to efficiently render the corresponding homoallylic boronates, which could be readily converted into valuable homoallylic alcohols or amines or 1,4-diboronates. This reaction features a broad substrate scope with good functional group compatibility that is complementary to the existing methods for the preparation of homoallylic boronates.
- Lou, Yixian,Qiu, Jian,Yang, Kai,Zhang, Feng,Wang, Chenglan,Song, Qiuling
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supporting information
p. 4564 - 4569
(2021/06/28)
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- Visible-light-promoted radical alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester: Synthesis of oxazolines
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An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.
- Ding, Hao,Huang, Panyi,Jin, Can,Su, Weike,Sun, Bin,Yan, Zhiyang,Zhao, Haiyun
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supporting information
(2021/10/29)
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- MnBr2 catalyzed regiospecific oxidative Mizoroki-Heck type reaction
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Herein, we report an unprecedented regiospecific oxidative Mizoroki-Heck type reaction for the synthesis of ɑ-difluoromethyl homoallylic alcohols. The reaction shows broad substrate scopes and high functional group tolerance. Late-stage functionalization of complex biologically active molecules demonstrates the synthetic potential of this transformation. Mechanistic study supports the involvement of MnBr2 catalyzed radical 1,2-silyl transfer.
- Chen, Xiang,Chen, Yi-Hung,Liu, Shanshan,Shen, Xiao,Zhu, Zhihong
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supporting information
(2021/11/27)
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- Experimental and Computational Studies of Palladium-Catalyzed Spirocyclization via a Narasaka-Heck/C(sp3or sp2)-H Activation Cascade Reaction
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The first synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem Narasaka-Heck/C(sp3 or sp2)-H activation reaction is reported here. The key step in this transformation is the activation of a δ-C-H bond via an in situ generated σ-alkyl-Pd(II) species to form a five-membered spiro-palladacycle intermediate. The concerted metalation-deprotonation (CMD) process, rate-determining step, and energy barrier of the entire reaction were explored by density functional theory (DFT) calculations. Moreover, a series of control experiments was conducted to probe the rate-determining step and reversibility of the C(sp3)-H activation step.
- Wei, Wan-Xu,Li, Yuke,Wen, Ya-Ting,Li, Ming,Li, Xue-Song,Wang, Cui-Tian,Liu, Hong-Chao,Xia, Yu,Zhang, Bo-Sheng,Jiao, Rui-Qiang,Liang, Yong-Min
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supporting information
p. 7868 - 7875
(2021/05/27)
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- Cationic nickel(II)-catalyzed hydrosilylation of alkenes: Role of p, n?type ligand scaffold on selectivity and reactivity
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Seven structurally similar cationic nickel(II)?alkyl complexes were synthesized by using a series of P, N ligands, and their reactivity was explored in the hydrosilylation of alkenes. More electron-rich phosphines enhanced the overall reactivity of the transformation; in contrast, groups on the imine donor had little impact. Overall, these catalysts displayed reactivity and selectivity that was previously unknown or very rare in nickel-catalyzed hydrosilylation. In reactions with Ph2SiH2, 1,2-disubstituted vinylarenes showed complete benzylic selectivity for silane addition, whereas terminal selectivity was observed for 1,1-disubstituted alkenes. The related PhSiH3 led to exclusively Markovnikov selectivity for monosubstituted vinylarenes with no competing double addition observed. Mechanistic investigations supported the hypothesis that a Ni?H functions as the active species in this catalytic hydrosilylation, which in turn also showed catalytic competence for the silane redistribution reaction, especially with sterically unhindered silanes.
- Hossain, Istiak,Schmidt, Joseph A.R.
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supporting information
p. 3441 - 3451
(2020/10/09)
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- Aqueous ZnCl2 Complex Catalyzed Prins Reaction of Silyl Glyoxylates: Access to Functionalized Tertiary α-Silyl Alcohols
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An efficient Prins reaction of silyl glyoxylates in the presence of an aqueous ZnCl2 complex as a catalyst was developed, providing functionalized tertiary α-silyl alcohols in high yields under mild conditions. A preliminary investigation indicated that the aqueous ZnCl2 complex acted as a dual functional catalyst of Br?nsted and Lewis acid to activate the carbonyl groups of silyl glyoxylates via a dual-activation model.
- Han, Man-Yi,Pan, Hong,Li, Pinhua,Wang, Lei
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p. 5825 - 5837
(2020/05/22)
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- Concurrent Formation of N-H Imines and Carbonyl Compounds by Ruthenium-Catalyzed C-C Bond Cleavage of β-Hydroxy Azides
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A commercial cyclopentadienylrutenium dicarbonyl dimer ([CpRu(CO)2]2) efficiently catalyzes the formation of N-H imines and carbonyl compounds simultaneously from β-hydroxy azides via C-C bond cleavage under visible light. Density functional theory calculations for the cleavage reaction support the mechanism involving chelation of alkoxy azide species and liberation of nitrogen as the driving force. The synthetic utility of the reaction was demonstrated by a new amine synthesis promoted by chemoselective allylation of imine and synthesis of isoquinoline.
- Lee, Jeong Min,Bae, Dae Young,Park, Jin Yong,Jo, Hwi Yul,Lee, Eunsung,Rhee, Young Ho,Park, Jaiwook
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supporting information
p. 4608 - 4613
(2020/06/05)
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- Additions of Aldehyde-Derived Radicals and Nucleophilic N-Alkylindoles to Styrenes by Photoredox Catalysis
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The consecutive addition of acyl radicals and N-alkylindole nucleophiles to styrenes was established, as well as some additional radical-nucleophile combinations. Both aryl and aliphatic aldehydes give reasonable yields. The reaction proceeds best for α-substituted styrenes, effectively creating a quaternary all-carbon center. Some iridium-based photoredox systems are catalytically active; furthermore, a base is needed in this transformation. Radicals are formed by reductive perester cleavage and hydrogen atom transfer.
- Klussmann, Martin,Lux, Marcel
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supporting information
(2020/04/30)
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- Synthesis of Tertiary Benzylic Nitriles via Nickel-Catalyzed Markovnikov Hydrocyanation of α-Substituted Styrenes
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The Markovnikov hydrocyanation of α-substituted styrenes enables the synthesis of tertiary benzylic nitriles under nickel catalysis. The Lewis-acid-free transformation features an unprecedented functional groups tolerance, including the-OH and-NH2 groups. A broad range of tertiary benzylic nitriles were obtained in good to excellent yields. In addition, an asymmetric version of this reaction was preliminarily investigated.
- Xing, Yidan,Yu, Rongrong,Fang, Xianjie
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supporting information
p. 1008 - 1012
(2020/02/04)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
-
supporting information
(2020/07/20)
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- Stereoselective Synthesis of Vinylcyclopropa[ b]indolines via a Rh-Migration Strategy
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A mild rhodium catalytic system has been developed to synthesize vinylcyclopropa[b]indolines through cyclopropanation of indoles with vinyl carbenoids generated from ring opening of cyclopropenes in situ. By employing a Rh-migration strategy, the products can be obtained with good to excellent E:Z ratios (≤99:1) and complete diastereoselectivity (≤99:1). This method is easy, has a low catalyst loading, and works for a broad range of functionalities.
- Guo, Pan,Sun, Wangbin,Liu, Yu,Li, Yong-Xin,Loh, Teck-Peng,Jiang, Yaojia
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supporting information
p. 5978 - 5983
(2020/08/05)
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- The Allylic Acetoxylation of 1,1-Disubstituted Alkenes Catalyzed by a Palladium(II)/Monothiadiazole Ligand System
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A palladium(II)/monothiadiazole ligand catalytic system and its application in catalyzing the acetoxylation of 1,1-disubstituted alkenes have been developed. With this newly designed monothiadiazole thioether ligand, the reaction showed a broad scope with respect to 1,1-disubstituted olefins, giving the corresponding products in yields of 30-86percent.
- Jin, Can,Li, Xiaohan,Sun, Bin,Wang, Jiayang,Yang, Jin,Yu, Chuangming,Zhang, Xun,Zhuang, Xiaohui
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p. 1479 - 1483
(2019/07/15)
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- Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2- a]pyridin-5-ones through Pummerer-Type Reactions
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N-Alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride-activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride-activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.
- Huang, Jingjia,Hu, Gang,An, Shaoyu,Chen, Dongding,Li, Minglei,Li, Pingfan
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p. 9758 - 9769
(2019/08/08)
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- A convenient access to allylic triflones with allenes and triflyl chloride in the presence of (EtO)2P(O)H
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A simple method for the preparation of allylic triflones from allenes and triflyl chloride in the presence of (EtO)2P(O)H has been developed. The features of this reaction are catalyst-free and simple starting substrates. This method tolerates diverse functional groups and substituted allylic triflones are obtained in moderate to good yields.
- Ni, Jixiang,Jiang, Yong,An, Zhenyu,Lan, Jingfeng,Yan, Rulong
-
supporting information
p. 7343 - 7345
(2019/06/27)
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- Chiral Br?nsted Acid Catalyzed Dynamic Kinetic Asymmetric Hydroamination of Racemic Allenes and Asymmetric Hydroamination of Dienes
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The first highly efficient and practical chiral Br?nsted acid catalyzed dynamic kinetic asymmetric hydroamination (DyKAH) of racemic allenes and asymmetric hydroamination of unactivated dienes with both high E/Z selectivity and enantioselectivity are described herein. The transformation proceeds through a new catalytic asymmetric model involving a highly reactive π-allylic carbocationic intermediate, generated from racemic allenes or dienes through a proton transfer mediated by an activating/directing thiourea group. This method affords expedient access to structurally diverse enantioenriched, potentially bioactive alkenyl-containing aza-heterocycles and bicyclic aza-heterocycles.
- Lin, Jin-Shun,Li, Tao-Tao,Jiao, Guan-Yuan,Gu, Qiang-Shuai,Cheng, Jiang-Tao,Lv, Ling,Liu, Xin-Yuan
-
supporting information
p. 7092 - 7096
(2019/04/26)
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- Copper-Catalyzed 1,2-Methoxy Methoxycarbonylation of Alkenes with Methyl Formate
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Reported here is a copper-catalyzed 1,2-methoxy methoxycarbonylation of alkenes by an unprecedented use of methyl formate as a source of both the methoxy and the methoxycarbonyl groups. This reaction transforms styrene and its derivatives into value-added β-methoxy alkanoates and cinnamates, as well as medicinally important five-membered heterocycles, such as functionalized tetrahydrofurans, γ-lactones, and pyrrolidines. A ternary β-diketiminato-CuI-styrene complex, fully characterized by NMR spectroscopy and X-ray crystallographic analysis, is capable of catalyzing the same transformation. These findings suggest that pre-coordination of electron-rich alkenes to copper might play an important role in accelerating the addition of nucleophilic radicals to electron-rich alkenes, and could have general implications in the design of novel radical-based transformations.
- Budai, Balázs,Leclair, Alexandre,Wang, Qian,Zhu, Jieping
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supporting information
p. 10305 - 10309
(2019/06/27)
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- Highly Enantioselective Iridium-Catalyzed Hydrogenation of 2-Aryl Allyl Phthalimides
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The iridium-catalyzed asymmetric hydrogenation of 2-aryl allyl phthalimides to afford enantioenriched β-aryl-β-methyl amines is presented. Recently developed Ir-MaxPHOX catalysts are used for this enantioselective transformation. The mild reaction conditions and the feasible removal of the phthalimido group makes this catalytic method easily scalable and of great interest to afford chiral amines. The importance of this new methodology is exemplified by the formal synthesis of (R)-Lorcaserin, OTS514, and enantiomerically enriched 3-methyl indolines.
- Cabré, Albert,Romagnoli, Elia,Martínez-Balart, Pol,Verdaguer, Xavier,Riera, Antoni
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supporting information
p. 9709 - 9713
(2019/11/19)
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- Copper-Catalyzed Enantio- and Diastereoselective Addition of Silicon Nucleophiles to 3,3-Disubstituted Cyclopropenes
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A highly stereocontrolled syn-addition of silicon nucleophiles across cyclopropenes with two different geminal substituents at C3 is reported. Diastereomeric ratios are excellent throughout (d.r.≥98:2) and enantiomeric excesses usually higher than 90 %, even reaching 99 %. This copper-catalyzed C?Si bond formation closes the gap of the direct synthesis of α-chiral cyclopropylsilanes.
- Zhang, Liangliang,Oestreich, Martin
-
supporting information
p. 14304 - 14307
(2019/11/13)
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- Synthesis of 2-Substituted Propenes by Bidentate Phosphine-Assisted Methylenation of Acyl Fluorides and Acyl Chlorides with AlMe3
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Bidentate phosphine-assisted methylenation of acyl fluorides and acyl chlorides with substituted with aryl, alkenyl, and alkyl groups trimethylaluminum afforded an array of 2-substituted propene derivatives. The addition of a catalytic amount of DPPM increased an efficiency of the reactions. Trimethylaluminum as the methylenation reagent not only eliminates the presynthesis of methylene transfer reagent, but provides an efficient method for the synthesis of a series of 2-substituted propenes.
- Wang, Xiu,Wang, Zhenhua,Asanuma, Yuya,Nishihara, Yasushi
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supporting information
p. 3640 - 3643
(2019/05/17)
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- Iridium-Catalyzed Isomerization of N-Sulfonyl Aziridines to Allyl Amines
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The Crabtree's reagent catalyzes the isomerization of N-sulfonyl 2,2-disubstituted aziridines to allyl amines. The selectivity of allyl amine vs imine is very high (up to 99/1). The unprecedented isomerization takes place in mild conditions without activation of the catalyst by hydrogen. The mechanism has been studied computationally by DFT calculations; instead of the usual hydrogenation of COD, the catalytic species is formed by a loss of the pyridine ligand. Approaching of aziridine to this unsaturated species leads to a carbocation intermediate through a low energy barrier. A metal-mediated tautomerization involving sequentially γ-H elimination and N-H reductive elimination affords selectively the allyl amine. The readiness of the CγH bond to participate in the H elimination step accounts for the selectivity toward the allyl amine product.
- Cabré, Albert,Sciortino, Giuseppe,Ujaque, Gregori,Verdaguer, Xavier,Lledós, Agustí,Riera, Antoni
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supporting information
p. 5747 - 5751
(2018/09/21)
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- Rhodium-Catalyzed Enantioconvergent Isomerization of Homoallylic and Bishomoallylic Secondary Alcohols
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We present herein an unprecedented enantioselective isomerization of homoallylic and bishomoallylic secondary alcohols, catalyzed by a commercially available rhodium-complex and a base. This catalytic redox-neutral process provides an effective access to chiral ketones in high efficiency and enantioselectivity, without the use of any stoichiometric reagent or generation of any waste. For the reaction of homoallylic alcohols, this system achieved not only a stereoconvergent access to chiral ketones bearing a β-stereocenter (up to 95%, 86% ee) but also a concomitant oxidative kinetic resolution of the alcohol substrates (S > 20). In the case of bishomoallylic alcohols, an intriguing ligand-induced divergent reactivity was observed. A terminal-to-internal alkene isomerization promoted by Rh/L7 followed by redox isomerization using Rh/BINAP system produced chiral ketones bearing a γ-stereocenter with high yield and enantioselectivity. Mechanistic studies provided strong support for the redox-isomerization pathway with chain walking of the key alkyl-Rh intermediate.
- Huang, Rui-Zhi,Lau, Kai Kiat,Li, Zhaofeng,Liu, Tang-Lin,Zhao, Yu
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supporting information
p. 14647 - 14654
(2018/11/06)
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- Electrochemically Enabled Carbohydroxylation of Alkenes with H2O and Organotrifluoroborates
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Unprecedented hydroxy-alkynylation and -alkenylation reactions of arylalkenes have been developed through electrochemically enabled addition of an organotrifluoroborate reagent and H2O across the double bond of the alkene. The use of electrochemistry to promote these oxidative alkene 1,2-difunctionalization reactions not only obviates the need for transition-metal catalysts and oxidizing reagents but also ensures high regio- and chemoselectivity to afford homopropargylic or homoallylic alcohols. The possibility of extending the electrochemical alkene difunctionalization strategy to other alkene carbo-heterofunctionalization reactions has been demonstrated.
- Xiong, Peng,Long, Hao,Song, Jinshuai,Wang, Yaohui,Li, Jian-Feng,Xu, Hai-Chao
-
supporting information
p. 16387 - 16391
(2018/11/23)
-
- Asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by Pd(II)-SunPhos complex
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An efficient asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by chiral Pd(II)/(S)-SunPhos complex was developed. A series of optically active homoallylic alcohols containing a CF3 group were obtained with high yields and excellent ee under mild conditions. Particularly, the reaction of isobutylene and trifluoropyruvate gave the desired product (90% yield, 98% ee) with catalyst loading as low as 0.01 mol% in dichloroethane/toluene.
- Jiang, Lili,Hu, Bei,Xie, Xiaomin,Zhang, Zhaoguo
-
supporting information
p. 6901 - 6905
(2017/10/31)
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- Iron-Catalyzed Acyloxyalkylation of Styrenes Using Hypervalent Iodine Reagents
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Iron-catalyzed acyloxyalkylation of styrene derivatives using hypervalent iodine reagents was achieved. The acyloxyalkylation reaction proceeded using various types of styrenes and hypervalent iodine reagents. The acyloxyalkylated products were obtained in moderate to good yields without loss of the functional groups. The reaction proceeded via the formation of radical species derived from hypervalent iodine reagents by decarboxylation.
- Wang, Zijia,Kanai, Motomu,Kuninobu, Yoichiro
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supporting information
p. 2398 - 2401
(2017/05/12)
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- Asymmetric Nitrone Synthesis via Ligand-Enabled Copper-Catalyzed Cope-Type Hydroamination of Cyclopropene with Oxime
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We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetric cyclopropene "hydronitronylation" process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic studies corroborate a CuI-catalytic profile featuring an olefin metalla-retro-Cope aminocupration process as the key C-N bond forming event. This conceptually novel reactivity enables the first example of highly enantioselective catalytic nitrone formation process and will likely spur further developments that may significantly expedite chiral nitrone synthesis.
- Li, Zhanyu,Zhao, Jinbo,Sun, Baozhen,Zhou, Tingting,Liu, Mingzhu,Liu, Shuang,Zhang, Mengru,Zhang, Qian
-
supporting information
p. 11702 - 11705
(2017/09/07)
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
-
supporting information
p. 12634 - 12637
(2017/12/02)
-
- Palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane: Synthesis of homoallylic boronic esters
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A palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane to afford the corresponding homoallylic organoboronic esters with moderate to excellent yields is reported. This novel transformation provides an efficient strategy for the construction of homoallylic organoboronic esters in one step with a broad substrate scope. It is proposed that the palladium-catalyzed oxidative allylic C-H bond activation process may be involved in the catalytic cycle.
- Li, Chunsheng,Li, Meng,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 66 - 69
(2017/12/27)
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- Iodine-Catalyzed Facile Approach to Sulfones Employing TosMIC as a Sulfonylating Agent
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A novel iodine-catalyzed functionalization of a variety of olefins and alkynes and direct decarboxylative functionalization of cinnamic and propiolic acids with TosMIC to provide access to various vinyl, allyl, and β-iodo vinylsulfones is described. This simple, efficient, and environmentally benign approach employing inexpensive molecular iodine as a catalyst demonstrates a versatile protocol for the synthesis of highly valuable sulfones, rendering it attractive to both synthetic and medicinal chemistry.
- Kadari, Lingaswamy,Palakodety, Radha Krishna,Yallapragada, Lakshmi Prapurna
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supporting information
p. 2580 - 2583
(2017/05/24)
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- Substrate Scope Evaluation of the Enantioselective Reduction of β-Alkyl-β-arylnitroalkenes by Old Yellow Enzymes 1-3 for Organic Synthesis Applications
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The substrate scope of the old yellow enzyme catalyzed reduction of β-alkyl-β-arylnitroalkenes is investigated. Compounds bearing either alkyl chains of increasing length at the carbon atom in position β to the nitro group or different substituents on the aromatic ring are prepared and submitted to bioreduction, to define the synthetic potential of this enantioselective reaction in the preparation of chiral fine chemicals. The versatility of the resulting nitroalkanes as chiral building blocks is shown by reducing the nitro group into a primary amine and by converting it into a carboxylic acid moiety by Meyer reaction. An "explosion" of chiral products can be observed by combining the highly enantioselective ene-reductase-mediated reduction of nitroalkenes with the chemical versatility of the nitro group.
- Bertolotti, Mattia,Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Santangelo, Sara
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p. 577 - 583
(2016/02/23)
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- Organic base-catalysed solvent-tuned chemoselective carbotrifluoromethylation and oxytrifluoromethylation of unactivated alkenes
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An unprecedented and efficient organic base-catalysed highly chemoselective carbo- and oxytrifluoromethylation of unactivated alkenes with Togni's reagent was developed. The switchable chemoselectivity was tuned by simply changing the organic base catalyst and solvent. Mechanistic studies indicated that a radical cyclization pathway for carbotrifluoromethylation in DMSO and a carbocation pathway for oxytrifluoromethylation in DCE were probably involved.
- Yang, Ning-Yuan,Li, Zhong-Liang,Ye, Liu,Tan, Bin,Liu, Xin-Yuan
-
supporting information
p. 9052 - 9055
(2016/07/21)
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- Iodothiocyanation/Nitration of Allenes with Potassium Thiocyanate/Silver Nitrite and Iodine
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Direct strategies for the iodothiocyanation and iodonitration of allenes have been developed. In this process, potassium thiocyanate/silver nitrite and molecular iodine are used as the source of SCN, ONO2and iodine to provide the desired products in moderate to good yields with high stereoselectivity. (Figure presented.).
- Yang, Xiaodong,She, Yue,Chong, Ya,Zhai, Huichun,Zhu, He,Chen, Baohua,Huang, Guosheng,Yan, Rulong
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supporting information
p. 3130 - 3134
(2016/10/09)
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- Iridium-Catalyzed Enantioselective Hydrogenation of β,β-Disubstituted Nitroalkenes
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A highly efficient, iridium-catalyzed, enantioselective hydrogenation of β,β-disubstituted nitroalkenes has been developed. Using a complex consisting of iridium and (S,S)-f-spiroPhos as the catalyst, a variety of β,β-disubstituted nitroalkenes were successfully hydrogenated to the corresponding chiral nitroalkanes with excellent enantioselectivities (up to 98% ee) and high turnover numbers (TON=1000).
- Liu, Man,Kong, Duanyang,Li, Meina,Zi, Guofu,Hou, Guohua
-
supporting information
p. 3875 - 3879
(2016/01/25)
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- Iron-Catalyzed Cross-Coupling of Alkenyl Acetates
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Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 C, 2 h) with a ligand-free catalyst (1-2 mol%). Iron clad: Acetates are underutilized electrophiles in metal-catalyzed cross-coupling reactions because of the strong alkenyl C-O bond and their propensity to engage in unwanted reactions. Combination of a ligand-free low-valent Fe catalyst with nucleophilic organomagnesium reagents, low temperature, and short reaction times results in highly selective cross-couplings with alkenyl acetates.
- G?rtner, Dominik,Stein, André Luiz,Grupe, Sabine,Arp, Johannes,Von Wangelin, Axel Jacobi
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supporting information
p. 10545 - 10549
(2015/09/02)
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- Catalytic enantioselective iodoaminocyclization of hydrazones
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The first catalytic enantioselective iodoaminocyclization of β,γ-unsaturated hydrazones has been developed with the help of a trans-1,2-diaminocyclohexane-derived bifunctional thiourea catalyst and allows for the direct access to δ2-pyrazolines containing a quaternary stereogenic center in high yield with good enantioselectivity (up to 95% yield and 95:5 er).
- Tripathi, Chandra Bhushan,Mukherjee, Santanu
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supporting information
p. 3368 - 3371
(2014/07/08)
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- Direct catalytic olefination of alcohols with sulfones
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The synthesis of terminal as well as internal olefins was achieved by the one-step olefination of alcohols with sulfones catalyzed by a ruthenium pincer complex. Furthermore performing the reaction with dimethyl sulfone under mild hydrogen pressure provides a direct route for the replacement of alcohol hydroxy groups by methyl groups in one step.
- Srimani, Dipankar,Leitus, Gregory,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 11092 - 11095
(2015/03/30)
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- Catalytic enantioselective iodoetherification of oximes
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Organocatalysis: The first catalytic enantioselective iodoetherification of oximes is developed using commercially available N-iodosuccinimide. In the presence of a dihydrocinchonidine-derived thiourea (10 mol %), β,γ-unsaturated oximes undergo facile iodoetherification to produce Δ2-isoxazolines containing a quaternary stereogenic center generally in high yield with good to excellent enantioselectivity. Copyright
- Tripathi, Chandra Bhushan,Mukherjee, Santanu
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supporting information
p. 8450 - 8453
(2013/09/02)
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- Highly enantioselective hydrogenation of β,β-disubstituted nitroalkenes
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Building the building blocks: A highly enantioselective hydrogenation of ?-aryl-?-alkyl disubstituted nitroalkenes 1 has been developed. This method results in enantiomerically pure nitroalkanes 2, which are versatile precursors for chemical synthesis.
- Li, Shengkun,Huang, Kexuan,Cao, Bonan,Zhang, Jiwen,Wu, Wenjun,Zhang, Xumu
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supporting information; experimental part
p. 8573 - 8576
(2012/09/10)
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- Free-amine-directed alkenylation of C(sp2)-H and cycloamination by palladium catalysis
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A new protocol for the palladium-catalyzed free-amine-directed alkenylation of C(sp2)-H bonds and cycloamination is described. Substituted biaryl-2-amines react with various alkenes, including electron-deficient alkenes, aryl alkenes and alkyl alkenes, to give the corresponding phenanthridines with exclusive regioselectivity. The use of α-branched styrenes leads to the formation of tricyclic compounds with a seven-membered amine ring. The method operates through a free-amine-directed alkenylation and a subsequent hydroamination cyclization reaction. Seven-membered cycloamination: A new protocol for the palladium-catalyzed free-amine-directed alkenylation of C(sp2)-H bonds and subsequent cycloamination is described (see scheme). Substituted biaryl-2-amines react with various alkenes to give the corresponding phenanthridines with exclusive regioselectivity. The use of α-branched styrenes leads to the formation of tricyclic compounds with a seven-membered amine ring. Copyright
- Liang, Zunjun,Ju, Long,Xie, Yongju,Huang, Lehao,Zhang, Yuhong
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supporting information
p. 15816 - 15821
(2013/01/16)
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- Method for synthesizing (E)-Anethol and Related Compounds By Cross Coupling Reaction of Potassium alllyltrifluroborate and 4-bromoanisole and aryl halides
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Methods of producing substituted and non-substituted beta-methyl styrene by a cross-coupling reaction are provided. The disclosure also provides for methods of preparing (E)-Anethol and related compounds by a cross coupling reaction of potassium allyltrifluoroborate and 4-bromoanisole and aryl halides. Compounds, compositions, and methods of treating disorders utilizing beta-methyl styrene are also provided.
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Page/Page column 4
(2012/01/15)
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- Readily available hydrogen bond catalysts for the asymmetric transfer hydrogenation of nitroolefins
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This paper focuses on readily accessible thiourea hydrogen bond catalysts derived from amino acids, whose steric and electronic features are modulated by their degree of substitution at the carbinol carbon center. These catalysts were applied in the asymmetric transfer hydrogenation of nitroolefins furnishing the chiral products in up to 99% yield and 86% enantiomeric excess. The proposed catalyst's mode of action is supported by mechanistic investigations.
- Schneider, Jakob F.,Lauber, Markus B.,Muhr, Vanessa,Kratzer, Domenic,Paradies, Jan
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supporting information; experimental part
p. 4323 - 4327
(2011/07/08)
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- Stereospecific decarboxylative allylation of sulfones
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Allyl sulfonylacetic esters undergo highly stereospecific, palladium-catalyzed decarboxylative allylation. The reaction allows the stereospecific formation of tertiary homoallylic sulfones in high yield. In contrast to related reactions that proceed at -100 °C and require highly basic preformed organometallics, the decarboxylative coupling described herein occurs under mild nonbasic conditions and requires no stoichiometric additives. Allylation of the intermediate α-sulfonyl anion is more rapid than racemization, leading to a highly enantiospecific process. Density functional theory calculations indicate that the barrier for racemization is 9.9 kcal/mol, so the barrier for allylation must be 9.9 kcal/mol.
- Weaver, Jimmie D.,Ka, Being J.,Morris, David K.,Thompson, Ward,Tunge, Jon A.
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supporting information; scheme or table
p. 12179 - 12181
(2010/10/03)
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- Improved preparative route toward 3-arylcyclopropenes
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A convenient preparative protocol for the synthesis of various 3-arylcyclopropenes in a multigram scale is disclosed. Optimization of the reaction conditions and isolation procedures allowed for significant improvement of the chemical yields of these strained products. The described protocol was used for efficient preparation of a series of 3-methyl-3-arylcyclopropenes possessing different substituents in the aromatic ring. The effect of substitution in the aryl group on the stability of 3-arylcyclopropenes, as well as the corresponding precursors, is discussed.
- Sherrill, William M.,Kim, Ryan,Rubin, Michael
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p. 8610 - 8617
(2008/12/21)
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- Highly enantioselective reduction of β,β-disubstituted aromatic nitroalkenes catalyzed by Clostridium sporogenes
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(Chemical Equation Presented) This is the first report of the use of Clostridium sporogenes extracts for enantioselective reduction of C=C double bonds of β,β-disubstituted (1) and α,β-disubstituted nitroalkenes (3). Crude enzyme preparations reduced aryl derivatives 1a-e and 1h, in 35-86% yield with ≥97% ee. Reduction of (E)- and (Z)-isomers of 1c gave the same enantiomer of 2c (≥99% ee). In contrast, α,β- disubstituted nitroalkene 3a was a poor substrate, yielding (S)-4a in low yield (10-20%), and the ee (30-70% ee) depended on NADH concentration. An efficient synthesis of a library of nitroalkenes 1 is described.
- Fryszkowska, Anna,Fisher, Karl,Gardiner, John M.,Stephens, Gill M.
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p. 4295 - 4298
(2008/12/20)
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- NEW COMPOUNDS I/418
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There is provided compounds of formula I, wherein R1 to R7 have meanings given in the description, which are useful in the prophylaxis and in the treatment of arrhythmias, in particular atrial and ventricular arrhythmias.
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Page/Page column 27
(2008/06/13)
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- Evidence for significant through-space and through-bond electronic coupling in the 1,4-diphenylcyclohexane-1,4-diyl radical cation gained by absorption spectroscopy and DFT calculations
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Photoinduced single-electron-transfer promoted oxidation of 2,5-diphenyl-l,5-hexadiene by using N-methylquinolinium tetrafluoroborate/ biphenyl co-sensitization takes place with the formation of an intense electronic absorption band at 476 nm, which is attributed to the 1,4-diphenylcyclohexane-1,4-diyl radical cation. The absorption maximum (λob) of this transient occurs at a longer wavelength than is expected for either the cumyl radical or the cumyl cation components. Substitution at the para positions of the phenyl groups in this radical cation by CH3O, CH3, F, Cl, and Br leads to an increasingly larger redshift of λob. A comparison of the ρ value, which was obtained from a Hammett plot of the electronic transition energies of the radical cations versus σ+, with that for the cumyl cation shows that the substituent effects on the transition energies for the 1,4-diarylcyclohexane-1,4-diyl radical cations are approximately one half of the substituent effects on the transition energies of the cumyl cation. The observed substitu_ent-induced redshifts of λob and the reduced sensitivity of λob to substituent changes are in accordance with the proposal that significant through-space and -bond electronic interactions exist between the cumyl radical and the cumyl cation moieties of the 1,4-diphenylcyclohexane-1,4-diyl radical cation. This proposal gains strong support from the results of density functional theory (DFT) calculations. Moreover, the results of time-dependent DFT calculations indicate that the absorption band at 476 nm for the 1,4-diphenylcyclohexane-1,4-diyl radical cation corresponds to a SOMO-3-SOMO transition.
- Ikeda, Hiroshi,Hoshi, Yosuke,Namai, Hayato,Tanaka, Futoshi,Goodman, Joshua L.,Mizuno, Kazuhiko
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p. 9207 - 9215
(2008/12/21)
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- The ritter reaction under truly catalytic bronsted acid conditions
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Simple organic acids like 2,4-dinitrobenzenesulfonic acid (DNBSA) catalyze the Ritter reaction of secondary benzylic alcohols giving rise to the corresponding N-benzylacetamides in usually high yields. Reactions can be conducted without exclusion of oxygen and without the need of dry solvents. With tertiary α,α-dimethylbenzylic alcohols a different pathway involving a formal dimerization reaction takes place under the acid-catalytic conditions used. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Sanz, Roberto,Martinez, Alberto,Guilarte, Veronica,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
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p. 4642 - 4645
(2008/03/12)
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