- Dual Nickel/Ruthenium Strategy for Photoinduced Decarboxylative Cross-Coupling of α,β-Unsaturated Carboxylic Acids with Cycloketone Oxime Esters
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Herein, a dual nickel/ruthenium strategy is developed for photoinduced decarboxylative cross-coupling between α,β-unsaturated carboxylic acids and cycloketone oxime esters. The reaction mechanism is distinct from previous photoinduced decarboxylation of α,β-unsaturated carboxylic acids. This reaction might proceed through a nickelacyclopropane intermediate. The C(sp2)-C(sp3) bond constructed by the aforementioned reaction provides an efficient approach to obtaining various cyanoalkyl alkenes, which are synthetically valuable organic skeletons in organic and medicinal chemistry, under mild reaction conditions. The protocol tolerates many critical functional groups and provides a route for the modification of complex organic molecules.
- Gao, Ang,Jiang, Run-Chuang,Liu, Chuang-Chuang,Liu, Qi-Le,Lu, Xiao-Yu,Xia, Ze-Jie
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supporting information
p. 8829 - 8842
(2021/06/30)
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- Visible-light promoted oxidative cyclization of cinnamic acid derivatives using xanthone as the photocatalyst
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We have developed an efficient photocatalytic synthesis of coumarin derivativesviaa tandem double bond isomerization/oxidative cyclization of cinnamic acids. Inexpensive and stable xanthone was used as the photocatalyst, and readily available Selectfluor was used as the oxidant. This method tolerates a wide range of functional groups and offers excellent chemical yields in general. Besides, the photocatalytic oxidative cyclization of cinnamic acid esters gives dimerized lignan-type products.
- Zhao, Bin,Xu, Bo
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supporting information
p. 568 - 573
(2021/02/06)
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- Palladium-Catalyzed Direct C-H Arylation of 3-Butenoic Acid Derivatives
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We report herein a direct method to synthesize 4-aryl-3-butenoic acid through a carboxylic-acid-directed oxidative Heck reaction. The various 4-aryl-3-butenoic acids are easily prepared in moderate to good yields. In view of the promising bioactivity of 4-phenyl-3-butenoic acid previously reported, its derivatives reported here may be bioactive.
- Yang, Shan,Liu, Lingling,Zhou, Zheng,Huang, Zhibin,Zhao, Yingsheng
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supporting information
p. 296 - 299
(2021/01/13)
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- Arylpyran Pseudoacid Racemization: Rate Estimation and Structural Influences
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Abstract: Arylpyran pseudoacids showed slow ring-opening to the oxocarboxylic acids, and fast ring-closure to the lactols (pseudoacids) in a process that amounts to racemization. Compounds studied were patterned on “Cooper’s Pseudoacid” [3-hydroxy-4,4-dim
- Fung, Jonathan,Duong, Truc-Vi,Braceros, Keean C. A.,Brooks, Marilyn L.,Schloesser-Lingscheit, Katie,Tagawa, Tristen K. S.,Wilson, Johanna M.,Jones, Kevin K.,Valente, Edward J.
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- Chemoselective reduction of ?,¢-unsaturated carbonyl and carboxylic compounds by hydrogen iodide
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The selective reduction of ?,¢-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an ? or ¢ position efficiently facilitated the reduction with good yield. The reaction was applicable to compounds bearing carboxylic acids and halogen atoms. Through the investigation of the reaction mechanism, it was found that Michael-type addition of iodide occurred to produce ¢-iodo compounds followed by the reduction of C-I bond via anionic and radical paths.
- Matsumoto, Shoji,Marumoto, Hayato,Akazome, Motohiro,Otani, Yasuhiko,Kaiho, Tatsuo
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p. 590 - 599
(2021/03/29)
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- Copper-Photocatalyzed Contra-Thermodynamic Isomerization of Polarized Alkenes
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The contra-thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)2/rac-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the E → Z isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good to excellent ratios. The mechanism of this process based on the transient formation of a chromophore was also studied.
- Bouillon, Jean-Philippe,Brégent, Thibaud,Poisson, Thomas
-
supporting information
p. 7688 - 7693
(2020/10/09)
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- Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed [3 + 2] Annulation of Vinyl Enolates with 1-Tosyl-2-vinylaziridine
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The synergistic combination of N-heterocyclic carbene organocatalysis and transition-metal catalysis for a formal [3 + 2] annulation between 3-substituted but-2-enoates and 1-tosyl-2-vinylaziridine was developed. This cooperative strategy provides a facile and efficient access to various functionalized (E)-3-ethylidene-4-vinylpyrrolidin-2-ones in a regioselective and stereoselective manner. The preliminary asymmetric studies were also performed, which indicated a potential for enantioselective annulation of vinyl enolate intermediates with transition-metal-π-allyl species.
- Gao, Jian,Zhang, Jianming,Fang, Shuaishuai,Feng, Jie,Lu, Tao,Du, Ding
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p. 7725 - 7729
(2020/10/09)
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- Synthesis and characterization of unsaturated diacyl and alkyl-acyl piperazine derivatives
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The aim of this study is to obtain new unsaturated piperazine compounds by the reactions of piperazine (1a) and piperazine derivatives (1b–1d) with acylation reactive groups (2a–2j). Methacryloyl piperazine (1b) was synthesized from the reaction of methacrylic anhydride with piperazine (1a). Acyl chlorides (2b–2d) were prepared from the reaction of thionyl chloride with carboxylic acids (3a–3c) obtained as a result of the reaction with malonic acid and suitable aldehyde (5-methylfuran-2-carbaldehyde for 3a, cinnamaldehyde for 3b, and thiophene-2-carbaldehyde for 3c), respectively, by literature methods. Acyl chlorides 2e and 2f were obtained from the reaction of commercially purchased carboxylic acids 3d and 3e with thionyl chloride. Acyl chlorides (2g–2j) were synthesized from the reaction of thionyl chloride with carboxylic acids (3d–3g) transformed from hydrolyzation of esters (4a–4d) obtained as a result of the reaction of triethyl phosphonoacetate with a suitable ketone (acetophenone for 4a, benzophenone for 4b, 1-(5-methylfuran-2-yl)ethan-1-one for 4c, and 1-(thiophen-2-yl)ethan-1-one for 4d), respectively, by literature methods. Unsaturated piperazine derivatives 5a and 5b were obtained from the reaction of 1b with 2b and 2e, respectively. In addition, from the reaction of 1b and acyl chlorides (2b–2j), unsaturated piperazines (5c–5k) were synthesized in medium to good yields (63%–84%). Also, 5l–5g and 5r–5w were obtained from the reaction of allyl piperazine (2c) and cinnamyl piperazine (2d) with acyl chlorides (2a–2f).
- Sari, Sait,ünalan, Seda,Yilmaz, Mehmet
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p. 1656 - 1671
(2020/01/03)
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- Enantioselective epoxidation of β,β-disubstituted enamides with a manganese catalyst and aqueous hydrogen peroxide
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Enantioselective epoxidation of β,β-disubstituted enamides with aqueous hydrogen peroxide and a novel manganese catalyst is described. Epoxidation is stereospecific and proceeds fast under mild conditions. Amides are disclosed as key functional groups to enable high enantioselectivity.
- Clarasó, Carlota,Vicens, Laia,Polo, Alfonso,Costas, Miquel
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supporting information
p. 2430 - 2435
(2019/03/29)
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- Pd-Catalyzed decarboxylative cross-coupling reactions of epoxides with α,β-unsaturated carboxylic acids
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A Pd-catalyzed decarboxylative cross-coupling of α,β-unsaturated carboxylic acids with cyclic and acyclic epoxides has been developed. Both β-monosubstituted and β-disubstituted unsaturated carboxylic acids, as well as conjugated diene unsaturated carboxylic acids are suitable reaction substrates. Substituted homoallylic alcohols were obtained in moderate to good yields. The product was obtained as a mixture of diastereomers favoring the anti diastereomer of the cyclic epoxides. This work provides a method for the modification of complex organic molecules containing α,β-unsaturated carboxylic acids.
- Lu, Xiao-Yu,Li, Jin-Song,Wang, Shi-Qun,Zhu, Yu-Jing,Li, Yue-Ming,Yan, Lu-Yu,Li, Jia-Mei,Wang, Jin-Yu,Zhou, Hai-Pin,Ge, Xiu-Tao
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supporting information
p. 11123 - 11126
(2019/09/20)
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- Chiral 1,3,2-Diazaphospholenes as Catalytic Molecular Hydrides for Enantioselective Conjugate Reductions
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Secondary 1,3,2-diazaphospholenes have a polarized P?H bond and are emerging as molecular hydrides. Herein, a class of chiral, conformationally restricted methoxy-1,3,2-diazaphospholene catalysts is reported. We demonstrate their catalytic potential in asymmetric 1,4-reductions of α,β-unsaturated carbonyl derivatives, including enones, acyl pyrroles, and amides, which proceeded in enantioselectivities of up to 95.5:4.5 e.r.
- Miaskiewicz, Solène,Reed, John H.,Donets, Pavel A.,Oliveira, Caio C.,Cramer, Nicolai
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supporting information
p. 4039 - 4042
(2018/03/13)
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- Transition-metal-free C-P bond formation via decarboxylative phosphorylation of cinnamic acids with P(O)H compounds
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A novel, transition-metal-free phosphorylation of cinnamic acids with P(O)H compounds has been developed via radical-promoted decarboxylation under mild conditions. This method provides simple, efficient, and versatile access to valuable (E)-alkenylphosphine oxides in satisfactory yields with a wide variety of substrates.
- Liu, Lixin,Zhou, Dan,Dong, Jianyu,Zhou, Yongbo,Yin, Shuang-Feng,Han, Li-Biao
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p. 4190 - 4196
(2018/04/14)
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- Construction of Multi-Substituted Benzenes via NHC-Catalyzed Reactions of Carboxylic Esters
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A carbene-catalyzed ester activation reaction for the synthesis of multi-substituted benzenes is developed. Tetra-substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than the quinones commonly used in related carbene-catalyzed reactions.
- Wu, Jichang,Mou, Chengli,Chi, Yonggui Robin
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p. 333 - 337
(2018/03/07)
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- Pd(II)/Bipyridine-Catalyzed Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Carboxylic Acids. Synthesis of β-Quaternary Carbons Substituted Carboxylic Acids
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Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.
- Liu, Rui,Yang, Zhenyu,Ni, Yuxin,Song, Kaixuan,Shen, Kai,Lin, Shaohui,Pan, Qinmin
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p. 8023 - 8030
(2017/08/14)
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- DMAP-Catalyzed [4 + 2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Ketones for Synthesis of α,β-Unsaturated δ-Lactones
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The DMAP-catalyzed [4 + 2] cycloaddition of α,β-unsaturated carboxylic acids with ketones furnishing α,β-unsaturated δ-lactones in good yields (up to 80%) is described, which is the first example of remote γ-C(sp3)-H activation of α,β-unsaturated carboxylic acids facilitated by DMAP, a pyridine-based catalyst. Copyright
- Jin, Jinghai,Xu, Qinchang,Deng, Weiping
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supporting information
p. 397 - 400
(2017/04/27)
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- Synthesis of 6-hydroxy-5,6-dihydro-2-pyrones and -pyridones by reaction of 4-aryl-6-trifluoromethyl-2-pyrones with water, hydrazine, and hydroxylamine
-
[Figure not available: see fulltext.] Reactions of 4-aryl-6-trifluoromethyl-2H-pyran-2-ones with sodium hydroxide followed by acidification provided the respective 6-hydroxy-5,6-dihydro derivatives, while the reactions of 4-aryl-6-trifluoromethyl-2H-pyran
- Usachev, Sergey A.,Usachev, Boris I.,Sosnovskikh, Vyacheslav Ya.
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p. 1294 - 1301
(2018/01/27)
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- One Photocatalyst, n Activation Modes Strategy for Cascade Catalysis: Emulating Coumarin Biosynthesis with (-)-Riboflavin
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Generating molecular complexity using a single catalyst, where the requisite activation modes are sequentially exploited as the reaction proceeds, is an attractive guiding principle in synthesis. This requires that each substrate transposition exposes a catalyst activation mode (AM) to which all preceding or future intermediates are resistant. While this concept is exemplified by MacMillan's beautiful merger of enamine and iminium ion activation, examples in other fields of contemporary catalysis remain elusive. Herein, we extend this tactic to organic photochemistry. By harnessing the two discrete photochemical activation modes of (-)-riboflavin, it is possible to sequentially induce isomerization and cyclization by energy transfer (ET) and single-electron transfer (SET) activation pathways, respectively. This catalytic approach has been utilized to emulate the coumarin biosynthesis pathway, which features a key photochemical E → Z isomerization step. Since the ensuing SET-based cyclization eliminates the need for a prefunctionalized aryl ring, this constitutes a novel disconnection of a pharmaceutically important scaffold.
- Metternich, Jan B.,Gilmour, Ryan
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supporting information
p. 1040 - 1045
(2016/02/05)
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- Enantioselective Hydrogenation of β,β-Disubstituted Unsaturated Carboxylic Acids under Base-Free Conditions
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An additive-free enantioselective hydrogenation of β,β-disubstituted unsaturated carboxylic acids catalyzed by the Rh-(R,R)-f-spiroPhos complex has been developed. Under mild conditions, a wide scope of β,β-disubstituted unsaturated carboxylic acids were hydrogenated to the corresponding chiral carboxylic acids with excellent enantioselectivities (up to 99.3% ee). This methodology was also successfully applied to the synthesis of the pharmaceutical molecule indatraline.
- Yan, Qiaozhi,Kong, Duanyang,Zhao, Wei,Zi, Guofu,Hou, Guohua
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p. 2070 - 2077
(2016/03/15)
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- EtAlCl2/2,6-Disubstituted Pyridine-Mediated Carboxylation of Alkenes with Carbon Dioxide
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α-Arylalkenes and trialkyl-substituted alkenes undergo carboxylation with CO2 in the presence of EtAlCl2 and 2,6-dibromopyridine to afford the corresponding α,β- and/or β,γ-unsaturated carboxylic acids. This reaction is suggested to proceed via the electrophilic substitution of EtAlCl2 with the aid of the base, followed by the carbonation of the resulting ate complex. This reaction can be applied to terminal dialkylalkenes by using a mixture of 2,6-di-tert-butylpyridine and 2,6-dibromopyridine.
- Tanaka, Shinya,Watanabe, Kota,Tanaka, Yuuki,Hattori, Tetsutaro
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supporting information
p. 2576 - 2579
(2016/06/15)
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- Pd-Catalyzed α-Selective C-H Functionalization of Olefins: En Route to 4-Imino-β-Lactams
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Pd-catalyzed α-olefinic C-H activation of simple α,β-unsaturated olefins has been developed. 4-imino-β-lactam derivatives were readily synthesized via activation of α-olefinic C-H bonds with excellent cis stereoselectivity. A wide range of heterocycles at the β-position are compatible with this reaction. The product of 4-imino-β-lactam derivatives can be readily converted to 2-aminoquinoline which exists extensively in pharmaceutical drugs and natural products.
- Kong, Wei-Jun,Liu, Yue-Jin,Xu, Hui,Chen, Yan-Qiao,Dai, Hui-Xiong,Yu, Jin-Quan
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p. 2146 - 2149
(2016/03/05)
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- Metal-Free Domino One-Pot Decarboxylative Cyclization of Cinnamic Acid Esters: Synthesis of Functionalized Indanes
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Trifluoroacetic acid promoted unprecedented domino reaction for the synthesis of diverse indanes starting from simple cinnamic acid esters is described. Their formation can be explained via acid triggered decarboxylation of cinnamic acid esters and subsequent inter/intramolecular cyclization. Overall process involves in the intramolecular cleavage of two σ-bonds (C-O and C-C) and inter/intramolecular construction of two/one C-C σ-bond(s). Significantly, this protocol was successful without the aid of any metal salts.
- Gopi Krishna Reddy, Alavala,Satyanarayana, Gedu
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p. 12212 - 12222
(2016/12/23)
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- Hydroxamic acids block replication of hepatitis c virus
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Intrigued by the role of protein acetylation in hepatitis C virus (HCV) replication, we tested known histone deacetylase (HDAC) inhibitors and a focused library of structurally simple hydroxamic acids for inhibition of a HCV subgenomic replicon. While known HDAC inhibitors with varied inhibitory profiles proved to be either relatively toxic or ineffective, structure-activity relationship (SAR) studies on cinnamic hydroxamic acid and benzo[b]thiophen-2-hydroxamic acid gave rise to compounds 22 and 53, which showed potent and selective anti-HCV activity and therefore are promising starting points for further structural optimization and mechanistic studies.
- Ai, Teng,Xu, Yanli,Qiu, Li,Geraghty, Robert J.,Chen, Liqiang
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p. 785 - 800
(2015/01/30)
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- N-Heterocyclic Carbene-Catalyzed Activation of Esters of N-Hydroxyphthalimide: A Highly Enantioselective Route to Chiral Dihydropyridinones Bearing an All Carbon Quaternary Stereogenic Center
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An N-heterocyclic carbene-catalyzed highly enantioselective [3 + 3] annulation reaction of N-hydroxyphthalimide (NHPI) 3,3-disubstituted acrylates and N-Ts ketimines was developed. In most cases, the desired chiral dihydropyridinone products bearing an all carbon quaternary stereogenic center could be obtained in good yields with excellent enantioselectivities (>99% ee's), which demonstrated the NHPI acrylates as a kind of excellent substrate in NHC-catalysis.
- Zhang, Zhiming,Zeng, Xiaofei,Xie, Danbo,Chen, Dongdong,Ding, Liyuan,Wang, Anna,Yang, Limin,Zhong, Guofu
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p. 5052 - 5055
(2015/11/03)
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- Isothiourea-mediated asymmetric functionalization of 3-alkenoic acids
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Isothiourea HBTM-2.1 promotes the catalytic asymmetric α- functionalization of 3-alkenoic acids through formal [2 + 2] cycloadditions with N-tosyl aldimines and formal [4 + 2] cycloadditions with either 4-aryltrifluoromethyl enones or N-aryl-N-aroyl diazenes, providing useful synthetic building blocks in good yield and with excellent enantiocontrol (up to >99% ee). Stereodefined products are amenable to further synthetic elaboration through manipulation of the olefinic functionality.
- Morrill, Louis C.,Smith, Samuel M.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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p. 1640 - 1655
(2014/03/21)
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- Synthesis of coumarins via PIDA/I2-mediated oxidative cyclization of substituted phenylacrylic acids
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A variety of functionalized coumarins were synthesized from substituted phenylacrylic acids via PIDA/I2-mediated and irradiation-promoted oxidative carbon-oxygen bond formation. Our studies show that the oxygen in the pendant carboxylic acid group cyclizes favorably to the aryl ring that is cis to it. The main advantages of this method include good functional group tolerance and the transition-metal-free characteristic. The Royal Society of Chemistry 2013.
- Li, Jinming,Chen, Huiyu,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 4311 - 4320
(2013/04/24)
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- Synthesis of substituted nitroolefins: A copper catalyzed nitrodecarboxylation of unsaturated carboxylic acids
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A novel, mild and convenient method for the nitrodecarboxylation of substituted cinnamic acid derivatives to their nitroolefins is achieved using a catalytic amount of CuCl (10 mol%) and tert-butyl nitrite (2 equiv.) as a nitrating agent in the presence of air. This reaction provides a useful method for the synthesis of β,β-disubstituted nitroolefin derivatives, which are generally difficult to access from other conventional methods. Additionally, this reaction is selective as the E-isomer of the acid derivatives furnishes the corresponding E-nitroolefins. One more salient feature of the method is, unlike other methods, no metal nitrates or HNO3 are employed for the transformation.
- Rokade, Balaji V.,Prabhu, Kandikere Ramaiah
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supporting information
p. 6713 - 6716
(2013/10/01)
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- A practical and convenient protocol for the synthesis of (E)-α,β-unsaturated acids
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α,β-Unsaturated acids are very useful and versatile reagents in organic synthesis. A novel, practical, and convenient catalytic protocol comprising FeCl3·6H2O (0.5 mol %) and H 2O (1 equiv) in CH3NO2 is described for the rapid synthesis of α,β-unsaturated acids with high E-stereoselectivity under both microwave and conventional heating conditions with high TON and TOF values. This powerful approach efficiently demonstrated the utility of biomass derived aldehydes to build chemical agents used as fuel additives. The method proved to be scalable to gram scale synthesis.
- Mohite, Amar R.,Bhat, Ramakrishna G.
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supporting information
p. 4564 - 4567
(2013/09/24)
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- Organocatalytic enantioselective γ-aminoalkylation of unsaturated ester: Access to pipecolic acid derivatives
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The direct γ-carbon functionalization of α,β-unsaturated esters via N-Heterocyclic Carbene (NHC) catalysis is disclosed. This catalytically generated nucleophilic γ-carbon undergoes highly enantioselective additions to hydrazones. The resulting δ-lactam products can be readily transformed to optically enriched pipecolic acid derivatives.
- Xu, Jianfeng,Jin, Zhichao,Chi, Yonggui Robin
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p. 5028 - 5031
(2013/10/22)
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- Key structural features of cis-cinnamic acid as an allelochemical
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1-O-cis-cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals isolated from Spiraea thunbergii Sieb. It is suggested that it derives its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. It was synthesized to confirm its structure and bioactivity, and also a series of cis-cinnamic acid analogues were prepared to elucidate the key features of cis-cinnamic acid for lettuce root growth inhibition. The cis-cyclopropyl analogue showed potent inhibitory activity while the saturated and alkyne analogues proved to be inactive, demonstrating the importance of the cis-double bond. Moreover, the aromatic ring could not be replaced with a saturated ring. However, the 1,3-dienylcyclohexene analogue showed strong activity. These results suggest that the geometry of the C-C double bond between the carboxyl group and the aromatic ring is essential for potent inhibitory activity. In addition, using several light sources, the photostability of the cinnamic acid derivatives and the role of the C-C double bond were also investigated.
- Abe, Masato,Nishikawa, Keisuke,Okuda, Katsuhiro,Shindo, Mitsuru,Fukuda, Hiroshi,Nakanishi, Kazunari,Tazawa, Yuta,Taniguchi, Tomoya,Park, So-Young,Hiradate, Syuntaro,Fujii, Yoshiharu
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p. 56 - 67,12
(2012/12/12)
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- Ruthenium-catalyzed asymmetric transfer hydrogenation of allylic alcohols by an enantioselective isomerization/transfer hydrogenation mechanism
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Reducing hazards: A asymmetric transfer hydrogen reaction was developed to reduce prochiral allylic alcohols in high yield and excellent enantioselectivity (see example). Mechanistic studies indicate a novel enantioselective isomerization/transfer hydrogenation mechanism. This new reaction is much safer than high-pressure hydrogenation using H2 gas. Copyright
- Wu, Ruoqiu,Beauchamps, Marie G.,Laquidara, Joseph M.,Sowa Jr., John R.
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supporting information; experimental part
p. 2106 - 2110
(2012/04/11)
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- Radical cyclizations of conjugated esters and amides with 3-oxopropanenitriles mediated by manganese(III) acetate
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Radical cyclizations of conjugated esters and amides with 3-oxopropanenitriles in presence of manganese(III) acetate produced ethyl 4-cyano-2,3-dihydrofuran-3-carboxylates and 4-cyano-2,3-dihydrofuran-3- carboxamides in good yields. The radical cyclizations of conjugated amides gave 2,3-dihydrofurans in better yields than that of conjugated esters. Moreover, the reactions of thienyl substituted amides and esters with 3-oxopropanenitriles afforded 2,3-dihydrofurans more efficiently than phenyl substituted ones. ARKAT-USA, Inc.
- Yilmaz, E. Vildan Burgaz,Yilmaz, Mehmet,Oektemer, Atilla
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experimental part
p. 363 - 376
(2011/09/20)
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- N-heterocyclic carbene-catalyzed cyclization of unsaturated acyl chlorides and ketones
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A straightforward synthesis of optically active trifluoromethyl dihydropyranones and spirocyclic oxindole-dihydropyranones has been realized by the chiral N-heterocyclic carbenes-catalyzed cyclization of α,β- unsaturated β-methylacyl chlorides with activated trifluoromethyl ketones or isatin derivatives. Copyright
- Shen, Li-Tao,Shao, Pan-Lin,Ye, Song
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p. 1943 - 1948
(2011/10/13)
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- Catalytic enantioselective construction of β-quaternary carbons via a conjugate addition of cyanide to β,β-disubstituted α,β-unsaturated carbonyl compounds
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The first general catalytic enantioselective conjugate addition of cyanide to β, β-disubstituted α,β-unsaturated ketones and N-acylpyrroles was developed using a strontium catalyst derived from Sr(O iPr)2 and new chiral ligand 5. The reaction exhibited excellent enantioselectivity and a wide substrate scope using 0.5-10 mol % catalyst. 1,4-Adducts containing β-quaternary carbons were exclusively produced over 1,2-adducts. ESI-MS analysis of the strontium catalyst indicated that the active catalyst was a trimetallic Sr/5 = 3:5 complex. The exclusive 1,4-selectivity was partly due to the ability of the strontium complex to promote both a retro-cyanation reaction from the 1,2-adducts and highly enantioselective conjugate cyanation.
- Tanaka, Yuta,Kanai, Motomu,Shibasaki, Masakatsu
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supporting information; experimental part
p. 8862 - 8863
(2010/08/21)
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- Catalytic asymmetric formation of δ-Lactones from Unsaturated acyl halides
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Previously unexplored enantiopure zwitterionic ammonium dienolates have been utilized in this work as reactive intermediates that act as diene components in hetero-Diels-Alder reactions (HDAs) with aldehydes to produce optically active δ-lactones, subunits of numerous bioactive products. The dienolates were generated in situ from E/Z mixtures of a,b- unsaturated acid chlorides by use of a nucleophilic quinidine derivative and Sn (OTf)2 as co-catalyst. The latter component was not directly involved in the cycloaddition step with aldehydes and simply facilitated the formation of the reactive dienolate species. The scope of the cycloaddition was considerably improved by use of a complex formed from Er- (OTf)3 and a simple commercially available norephedrine-derived ligand that tolerated a broad range of aromatic and heteroaromatic aldehydes for a cooperative bifunctional Lewis-acid-/ Lewis-base-catalyzed reaction, providing a,b-unsaturated d-lactones with excellent enantioselectivities. Mechanistic studies confirmed the formation of the dienolate intermediates for both catalytic systems. The active ErIII complex is most likely a monomeric species. Interestingly, all lanthanides can catalyze the title reaction, but the efficiency in terms of yield and enantioselectivity depends directly on the radius of the Ln III ion. Similarly, use of the pseudolanthanides ScIII and YIII also resulted in product formation, whereas the larger La III and other transition metal salts, as well as main group metal salts, proved to be inefficient. In addition, various synthetic transformations of 6- CCl3- or 4-silyl-substituted α,β-unsaturated d-lactones, giving access to a number of valuable δ-lactone building blocks, were investigated.
- Tiseni, Paolo S.,Peters, Rene
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supporting information; experimental part
p. 2503 - 2517
(2010/09/03)
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- Catalytic asymmetric formation of δ-lactones by [4+2] cycloaddition of zwitterionic dienolates generated from α,β-unsaturated acid chlorides
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Smooth elaboration: Versatile δ-lactone building blocks are provided by tertiary amine-catalyzed asymmetric [4+2] cycloadditions of α,β-unsaturated acid chlorides and the electron-poor aldehyde chloral (see scheme). Silyl-substituted acid chlorides (R1 = R 3Si) can be used for the diastereoselective synthesis of β-hydroxy-δ-lactones possessing quaternary stereocenters. (Chemical Equation Presented).
- Tiseni, Paolo S.,Peters, Rene
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p. 5325 - 5328
(2008/03/18)
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- Two-carbon homologation of ketones via sily ketene acetals: Synthesis of α,β-unsaturated acids and α-trimethylsilyl δ-ketoacids
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The reaction of C,O,O-tris(trimethylsilyl)ketene acetal 1 with saturated, cyclic and aromatic ketones 2 proceeds smoothly in the presence of titanium chloride to give (E)-α,β-unsaturated carboxylic acids 3 with fairly good stereoselectivity. With α,β-unsa
- Bellassoued, Moncef,Mouelhi, Sinda,Fromentin, Pierre,Gonzalez, Aurélien
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p. 2172 - 2179
(2007/10/03)
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- N-azabicyclo-amide derivatives
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Compounds of the general formula I wherein A represents: D represents oxygen, or sulfur and R1, R2and R3are as defined in the specification, enantiomers thereof, pharmaceutically-acceptable salts thereof, processes for preparing them, pharmaceutical compositions containing them and their use in therapy, especially in the treatment or prophylaxis of psychotic disorders and intellectual impairment disorders.
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Page column 22
(2010/02/05)
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- Mizoroki-Heck arylation of α,β-unsaturated acids with a hybrid fluorous ether, F-626: Facile filtrative separation of products and efficient recycling of a reaction medium containing a catalyst
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The Mizoroki-Heck reaction was carried out using a fluorous ether F-626 as the solvent and a fluorous Pd carbene complex as the catalyst. When carboxylic acids are the products, separation of both the F-626 and the Pd catalyst from the products can be conveniently carried out by simple filtration. The F-626 filtrates containing the Pd catalyst can be recycled.
- Fukuyama, Takahide,Arai, Masashi,Matsubara, Hiroshi,Ryu, Ilhyong
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p. 8105 - 8107
(2007/10/03)
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- (E)-Selective Horner-Wadsworth-Emmons reaction of aryl alkyl ketones with bis(2,2,2-trifluoroethyl)phosphonoacetic acid
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The stereoselective Horner-Wadsworth-Emmons reaction of aryl alkyl ketones with bis(2,2,2-trifluoroethyl)phosphonoacetic acid utilizing lithium hexamethyldisilazide in DMF afforded (E)-α,β-unsaturated carboxylic acids as the major products.
- Sano, Shigeki,Takemoto, Yuka,Nagao, Yoshimitsu
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p. 8853 - 8855
(2007/10/03)
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- Palladium-catalysed cross-coupling of iodovinylic acids with organometallic reagents. Selective synthesis of 3,3-disubstituted prop-2-enoic acids
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3,3-Disubstituted prop-2-enoic acids were selectively prepared in good yields under mild experimental conditions via palladium-catalysed cross-coupling of 3-substituted 3-iodobut-2-enoic acids with miscellaneous organometallic reagents using dichlorobis(acetonitrile)palladium(II) as catalyst and DMF as solvent.
- Abarbri, Mohamed,Thibonnet, Jér?me,Parrain, Jean-Luc,Duchêne, Alain
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p. 543 - 551
(2007/10/03)
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- Nickel-promoted alkylative or arytative carboxylation of alkynes
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Formula presented Nickel-promoted alkylative or arylative carboxylation of terminal alkynes via a carbon dioxide fixation process was investigated. In the presence of a stoichiometric amount of a zero-valent nickel complex, the reaction of alkynes with CO
- Takimoto, Masanori,Shimizu, Kazuya,Mori, Miwako
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p. 3345 - 3347
(2007/10/03)
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- Anti-viral method
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PCT No. PCT/US97/07431 Sec. 371 Date Jan. 6, 1999 Sec. 102(e) Date Jan. 6, 1999 PCT Filed May 2, 1997 PCT Pub. No. WO97/41846 PCT Pub. Date Nov. 13, 1997The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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- Urea, thiourea and guanidine compounds and their use as anti-viral agents
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The present invention provides compounds which inhibit an envelope virus by inhibiting the fusion of the virus with the host cell. The virus may be inhibited in an infected cell, a cell susceptible of infection or a mammal in need thereof.
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- Highly efficient enantioselective synthesis of optically active carboxylic acids by Ru(OCOCH3)2[(S)-H8-BINAP]
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In the presence of a catalytic amount of Ru(OCOCH3)2[(S)-H8-BINAP] [H8-BINAP = 2,2′-bis-(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′- octahydro-1,1′-binaphthyl], the asymmetric hydrogenation of α,β- and β,γ-unsaturated carboxylic acids afforded the corresponding saturated carboxylic acids in higher enantiomeric excesses and at faster reaction rates than those using the Ru(OCOCH3)2[(R)-BINAP] catalyst [BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]. The hydrogenation of (E)-2-alkyl-2-alkenoic acids by the H8-BINAP catalyst system produced saturated acids in 95-97% ee. 2-Methylcinnamic acid was treated with H8-BINAP-Ru(II) complex as a catalyst to yield a hydrogenated product in much higher ee than that produced by BINAP-Ru(II) (89 and 30% ee, respectively). This homogeneous catalysis using H8-BINAP-Ru(II) established a promising synthetic route to (S)-ibuprofen in up to 97% ee. Asymmetric hydrogenation of β-disubstituted acrylic acids also proceeded smoothly with good enantioselectivities (70-93% ee). In addition, the hydrogenation of trisubstituted acrylic acids (up to 88% ee) was investigated. Hydrogen pressure effect on the sense and level of enantioselection was shown to be substrate dependent. The difference between the H8-BINAP- and BINAP-Ru(II) complexes was also discussed.
- Uemura, Toshitsugi,Zhang, Xiaoyoung,Matsumura, Kazuhiko,Sayo, Noboru,Kumobayashi, Hidenori,Ohta, Tetsuo,Nozaki, Kyoko,Takaya, Hidemasa
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p. 5510 - 5516
(2007/10/03)
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- Activation of C-O and C-N Bonds in Allylic Alcohols and Amines by Palladium Complexes Promoted by CO2. Synthetic Applications to Allylation of Nucleophiles, Carbonylation, and Allylamine Disproportionation
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The direct activation of the C-O bonds in allylic alcohols catalyzed by palladium complexes has been accelerated by carrying out the reactions under CO2. On reaction with diethylamine, allyl alcohol can be converted into N,N-diethylallylamine in the presence of palladium complexes at room temperature under normal pressure of carbon dioxide. Allylation of various carbon nucleophiles such as β-keto esters and β-diketones can be achieved by using allylic alcohols directly in the presence of palladium complexes and CO2. Direct carbonylation of allylic alcohols into unsaturated carboxylic acids can be catalyzed by palladium complexes under the pressure of CO and CO2. Disproportionation of diallylamine into triallylamine and allylamine is also catalyzed by palladium complexes in the presence of CO2. On the basis of studies on the behavior of η3-allylpalladium hydrogencarbonate complexes with the nucleophiles, mechanisms are proposed to account for the palladium-catalyzed allylation processes influenced by CO2.
- Sakamoto, Masato,Shimizu, Isao,Yamamoto, Akio
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p. 1065 - 1078
(2007/10/03)
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- Stereospecific synthesis of (Z) or (E)-3-methylalk-2-enoic acids
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The palladium catalysed coupling of organozinc or organotin reagents with 3-iodobut-2(or 3)-enoic acid is stereoselective and affords Z (or E)-3-methylalk-2-enoic acids. The method was applied to the synthesis of the E and Z stereoisomers of ocimenones and pseudo-tagetones.
- Abarbri,Parrain,Duchene
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p. 2469 - 2472
(2007/10/02)
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- Straightforward synthesis of α,β-unsaturated acids and derivatives
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A general C2 vinylic homologation from carbonyl compounds (aldehydes or ketones) which leads to various α,β-insaturated acids, esters and amides, is described.
- Tellier, Frederique,Sauvetre, Raymond
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p. 5433 - 5436
(2007/10/02)
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- Enantioselective Conjugate Reduction of α,β-Unsaturated Carboxamides with Semicorrin Cobalt Catalysts
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Chiral semicorrin cobalt complexes, prepared in situ from cobalt(II) chloride and the free ligands, are efficient, highly enantioselective catalysts for the conjugate reduction of α,β-unsaturated carboxamides with sodium borohydride.Enantiomeric excesses of up to 99percent, essentially quantitative yields, and high substrate/catalyst ratios (1000-10 000:1) are attractive attributes of this catalytic process.
- Matt, Peter von,Pfaltz, Andreas
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p. 691 - 700
(2007/10/02)
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- Carbonylation of Vinyl Halides with Carbonylcobalt
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The reactions of both (E)-β-bromostyrene (E)-(1a) and its Z-isomer (Z)-(1a) with octacarbonyldicobalt in the presence of methyl iodide and calcium hydroxide at 20 deg C in dioxane-water under carbon monoxide (1 atm) gave (E)-cinnamic acid (E)-(2a) exclusively.In contrast, with (E)-1-bromo-2-phenylpropene (E)-(1b), the thermodynamically less stable (Z)-3-phenylbut-2-enoic acid (Z)-(2b) was obtained as the major product together with the (E)-isomer (E)-(2b).The carbonylation of 3-chloroprop-2-enols (7a-f) gave the corresponding furan-2(5H)-ones (8a-f) in good yield.
- Miura, Masahiro,Okuro, Kazumi,Hattori, Ayako,Nomura, Masakatsu
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- Straightforward Synthesis of 2-Alkenoic Acids from the Corresponding Saturated Aldehydes
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2-Alkenoic acids may be prepared in good yields from saturated aldehydes via α-selenenylation with 4-(phenylseleno)morpholine formed in situ, followed by hydrogen peroxide oxidation.The actual oxidizing agent is benzeneperseleninic acid which is formed in the reaction medium.
- Outurquin, Francis,Paulmier, Claude
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p. 690 - 691
(2007/10/02)
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