- Substituent-induced delocalization effects on hydrogen-bonding interaction in poly(N-phenyl methacrylamide) derivatives
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Within small molecules, the hydrogen-bonding behaviors affected by delocalization have been studied thoroughly, but rare publication in macromolecules. Therefore, three poly(N-phenyl methacrylamide)s, poly(N-phenyl methacrylamide) (PNPAA), poly(N-4-methox
- Kuo, Shiao-Wei,Lin, Chien-Ting,Chen, Jem-Kun,Ko, Fu-Hsiang,Chang, Feng-Chih,Jeong, Kwang-Un
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Read Online
- A general strategy for the synthesis of α-trifluoromethyl- And α-perfluoroalkyl-β-lactamsviapalladium-catalyzed carbonylation
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β-Lactam compounds play a key role in medicinal chemistry, specifically as the most important class of antibiotics. Here, we report a novel one-step approach for the synthesis of α-(trifluoromethyl)-β-lactams and related products from fluorinated olefins, anilines and CO. Utilization of an advanced palladium catalyst system with the Ruphos ligand allows for selective cycloaminocarbonylations to give diverse fluorinated β-lactams in high yields.
- Beller, Matthias,Hao, Meng,Huang, Wei-Heng,Li, Yang,Neumann, Helfried,Sun, Ning,Zhang, Cai-Lin
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Read Online
- Bromo Radical-Mediated Photoredox Aldehyde Decarbonylation towards Transition-Metal-Free Hydroalkylation of Acrylamides at Room Temperature
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Herein, we report a visible-light-mediated hydroalkylation reaction of alkenes using easily available aldehydes as alkyl sources via bromo radical-promoted photoredox decarbonylation. This protocol provides an alternative entry to C(sp3)?C(sp3) bond formation and features considerable advantages including mild and clean reaction conditions, obviation for transition-metal catalyst, and good functional group compatibility.
- Sun, Zhaozhao,Huang, Huawen,Wang, Qiaolin,Deng, Guo-Jun
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supporting information
p. 453 - 458
(2021/12/03)
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- Photoredox Cyclization of N-Arylacrylamides for Synthesis of Dihydroquinolinones
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Metal- and additive-free photoredox cyclization of N-arylacrylamides is herein reported that provides a concise access to the formation of dihydroquinolinones. In this protocol, sustainable visible light was used as the energy source, and the organic light-emitting molecule 4CzIPN served as the efficient photocatalyst. This reaction system features exclusive 6-endo-trig cyclization selectivity with a generally good yield of a range of functionalized dihydroquinolinones and dihydrobenzoquinolinones. Mechanistical studies reveal the feasibility of both 1,3-H shift and intersystem crossing of the diradical intermediate.
- Liu, Zhaosheng,Zhong, Shuai,Ji, Xiaochen,Deng, Guo-Jun,Huang, Huawen
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supporting information
p. 349 - 353
(2021/12/27)
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- Reactions of 2,3-Dibromo-2-methylpropanamides Promoted by Potassium tert-Butoxide
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Abstract: 2,3-Dibromo-2-methylpropanamides with different substituents on the nitrogen atom were synthe-sized, and their transformations by the action of potassium tert-butoxide in THF were studied. 2,3-Dibromo-N-(4-methoxyphenyl)-2-methylpropanamide and 2,3-dibromo-N-(2,5-dibromo-4-methoxyphenyl)-2-methyl-propan-amide reacted with 1–2 equiv of t-BuOK to give the corresponding N-substituted 3-bromo-3-methyl- and 3-methylideneazetidin-2-ones with acceptable yields and selectivity. Increase of the amount of t-BuOK to 3–5 equiv led to significant reduction of the yield of vinyl bromides and 3-methylideneazetidin-2-ones. On the other hand, the reaction of 2,3-dibromo-N-(tert-butyl)-2-methylpropanamide with t-BuOK afforded 3-(tert-bu-toxymethyl)-1-tert-butylazetidin-2-one with a good yield and selectivity.
- Galeeva, A. M.,Miftakhov, M. S.,Selezneva, N. K.,Valiullina, Z. R.
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p. 1643 - 1649
(2021/12/13)
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- A benzene-bridged divanadium complex-early transition metal catalyst for alkene alkylarylation with PhI(O2CR)2viadecarboxylation
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The synthesis, structure and catalytic activity of a benzene-bridged divanadium complex were comprehensively studied. The reduction of (Nacnac)VCl2(1) (Nacnac = (2,6-iPr2C6H3NCMe)2HC) supported by β-diketiminate with potassium graphite (KC8) by employing benzene as the solvent allows access to the benzene-bridged inverted-sandwich divanadium complex (μ-η6:η6-C6H6)[V(Nacnac)]2(2a), which can catalyze alkene alkylarylation with hypervalent iodine(iii) reagents (HIRs)viadecarboxylation to generate regioselectively diverse indolinones. Furthermore, the mild nature of this reaction was amenable to a wide range of functionalities on alkenes and HIRs. Mechanistic studies revealed a relay sequence of decarboxylative radical alkylation/radical arylation/oxidative re-aromatization.
- Zhang, Lei,Zhou, Hongfei,Bai, Shaokun,Li, Shaodan
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supporting information
p. 3201 - 3206
(2021/03/16)
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- Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
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A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
- Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
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supporting information
(2021/12/10)
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- Hypervalent Iodine Mediated Oxidative Cyclization of Acrylamide N-Carbamates to 5,5-Disubstituted Oxazolidine-2,4-diones
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A metal-free oxidative cyclization of N-Boc-acrylamides with (diacetoxyiodo)benzene in acetic acid produced 5,5-disubstituted oxazolidine-2,4-diones with the formation of a C-O bond in moderate to excellent yields. In addition, the reaction was diastereospecific with N-Boc-2,3-dimethylacrylamides and proceeded with phenyl migration in the case of an N-Boc-2-phenylacrylamide to generate a 5-acetoxy-5-benzyloxazolidine-2,4-dione.
- Duddupudi, Anantha Lakshmi,Pandey, Pankaj,Vo, Hien,Welsh, Colin L.,Doerksen, Robert J.,Cuny, Gregory D.
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p. 7549 - 7557
(2020/06/03)
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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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supporting information
p. 1479 - 1483
(2019/07/15)
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- Regioselective Acetoxylation of Terminal Olefins Using a Palladium(II)–Thiadiazole Catalyst
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First-time use of a palladium(II)–thiadiazole catalyst in the allylic oxidation of terminal olefins to linear allylic acetates. Employing this strategy, a range of allylic esters (20 examples) were synthesized in 43 % to 80 % yield with excellent regio- and stereoselectivities.
- Li, Xiaohan,Sun, Bin,Zhou, Jiadi,Jin, Can,Yu, Chuangming
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supporting information
p. 2635 - 2638
(2019/04/04)
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- Synthesis of Perfluoroalkyl-Substituted Oxindoles through Organophotoredox-Catalyzed Perfluoroalkylation of N-arylacrylamides with Perfluoroalkyl Iodides
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An efficient process was developed for the perfluoroalkylation of N -arylacrylamides through an organocatalyzed photoredox/cyclization reaction of N -arylacrylamides with inexpensive perfluoroalkyl iodide reagents. The reaction employs an inexpensive organic dye, eosin Y, as the photoredox catalyst and is run under irradiation by a 26 W LED lightbulb.
- Yang, Zhiyong,Tang, Anjiang
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supporting information
p. 1061 - 1066
(2019/05/24)
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- Catalyst-free and selective trifluoromethylative cyclization of acryloanilides using PhICF3Cl
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Trifluoromethylation-triggered cyclization of alkenes provides a useful route to CF3-containing cyclic compounds. Current approaches to generate CF3-based initiators from a CF3 source require a catalyst or an activator. This work describes a catalyst-free protocol to innately produce electrophilic CF3 species from PhICF3Cl for trifluoromethylative cyclization of acryloanilides. A new domino biscyclization of dienes has been developed leading to trifluoroethylated tetrahydroindenoquinolinones with chemo- and stereo-selectivity.
- Guo, Jia,Xu, Cong,Wang, Ling,Huang, Wanqiao,Wang, Mang
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supporting information
p. 4593 - 4599
(2019/05/17)
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- Nickel-Catalyzed Transformation of Diazoacetates to Alkyl Radicals Using Alcohol as a Hydrogen Source
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A nickel-catalyzed transformation of diazoacetates to α-carbonyl methylene radicals has been disclosed in the presence of hyperoxide using ethanol as a hydrogen source and solvent. This strategy is successfully applied in the formation of indolin-2-ones or 1,4-dicarbonyl compounds from acrylamides or enamides in moderate to good yields. These reactions undergo radical addition onto C-C double bonds followed by a cyclization/oxidation or an oxidation/hydrolysis process, respectively.
- Zhao, Jingjing,Li, Pan,Xu, Yaohua,Shi, Yixin,Li, Fuwei
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supporting information
p. 9386 - 9390
(2019/11/28)
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- Synthesis of oxindoles via Cu-mediated reactions between N-phenylacrylamides and ethyl 2-bromo-2-methylpropionate
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A novel way of synthesizing alkylated oxindoles via Cu-mediated atom transfer radical addition reaction between N-phenylacrylamides and ethyl 2-bromo-2-methylpropionate has been described. It was found that the use of N,N,N′,N′-1,1,2,2,-tetramethylethylenediamine as ligand was important for achieving good yields. Additionally, the use of DMSO as solvent and running the reaction at 130 °C were also crucial. In some cases, the product can be further brominated when the reaction temperature was raised to 150 °C.
- Liu, Da,Zhuang, Shaobo,Chen, Xiang,Yu, Lin,Yu, Yongqi,Hu, Liang,Tan, Ze
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supporting information
p. 612 - 616
(2018/01/18)
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- Iron-Catalyzed Synthesis of Oxindoles: Application to the Preparation of Pyrroloindolines
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A novel and highly efficient synthetic approach to pyrroloindolines has been developed. The process is based on tandem radical addition/cyclization with inexpensive iron catalyst. This method tolerates a wide range of N-methyl-N-arylacrylamides as well carbamoyl radicals, providing access to a variety of functionalized 3,3-disubstituted oxindoles, key intermediates for many bioactive pyrroloindolines such as (±)-esermethole, (±)-deoxyeseroline, and (±)-physovenol methyl ether.
- Correia, Valquírio G.,Abreu, Juliana C.,Barata, Caio A. E.,Andrade, Leandro H.
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supporting information
p. 1060 - 1063
(2017/03/15)
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- Visible light sensitization of benzoyl azides: Cascade cyclization toward oxindoles: Via a non-nitrene pathway
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Visible light sensitization of benzoyl azides was examined in reaction with N-phenylmethacrylamides to afford biologically important oxindoles and spirooxindoles via a cascade cyclization under mild reaction conditions. Mechanistic studies suggested a non-nitrene pathway, where triplet benzoyl azides act as the reactive intermediate.
- Bagal, Dattatraya B.,Park, Sung-Woo,Song, Hyun-Ji,Chang, Sukbok
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supporting information
p. 8798 - 8801
(2017/08/09)
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- High-valent palladium-promoted formal Wagner-Meerwein rearrangement
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An oxy-palladation, formal Wagner-Meerwein rearrangement and fluorination cascade has been established for generating fluorinated oxazolidine-2,4-diones and oxazolidin-2-ones. The reaction has a broad substrate scope in which both aryl and alkyl groups can be utilized as efficient migrating groups. Experimental evidence suggests that the reaction is initiated by anti-oxy-palladation of the olefin, followed by oxidative generation of an alkyl PdIV intermediate and a concerted migration-fluorination.
- Wu, Hongmiao,Yang, Bin,Zhu, Lin,Lu, Ronghua,Li, Guigen,Lu, Hongjian
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supporting information
p. 5804 - 5807
(2016/11/29)
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- Disulfides as Sulfonylating Precursors for the Synthesis of Sulfone-Containing Oxindoles
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The first facile one-pot synthesis of sulfone-containing oxindoles with easily accessible disulfides as the sulfonylating precursors is described. This reaction occurs smoothly under transition metal-free conditions and shows excellent functional group tolerance, allowing the facile and efficient green synthesis of various sulfone-containing oxindoles in aqueous solution. Preliminary mechanistic studies reveal that both water (H2O) and potassium persulfate (K2S2O8) can be the oxygen source of the sulfone groups in the products. (Figure presented.).
- Zhang, Ming-Zhong,Ji, Peng-Yi,Liu, Yu-Feng,Xu, Jing-Wen,Guo, Can-Cheng
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supporting information
p. 2976 - 2983
(2016/09/16)
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- Metal-free arylalkylation of N -aryl acrylamides with azobisalkylnitriles
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A novel metal-free arylalkylation of N-aryl acrylamides with readily available azobisalkylnitriles leading to cyano-containing oxindoles has been developed. The use of readily available azobisalkylnitriles and DTBP as oxidant makes this protocol environmentally benign and practical.
- Tian, Qingshan,He, Ping,Kuang, Chunxiang
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supporting information
p. 681 - 687
(2015/03/14)
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- Light-induced BiOBr nanosheets accelerated highly regioselective intermolecular trifluoromethylation/arylation of alkenes to synthesize CF3-containing aza-heterocycles
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A light-induced, BiOBr nanosheets accelerated intermolecular one-pot tandem trifluoromethylation/arylation of alkenes was presented. With this method, a series of CF3-containing aza-heterocycles with high selectivity were fabricated in moderate to good yields. Preliminary mechanistic studies revealed that the exceptional transformation was originated from the synergistic effect of photogenerated electrons and holes. Density function theory (DFT) was adopted to understand the high selectivity of this photocatalytic chemical transformation.
- Liu, Cuibo,Zhao, Weiwei,Huang, Yi,Wang, Hongming,Zhang, Bin
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supporting information
p. 4344 - 4351
(2015/06/08)
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- UV light-mediated difunctionalization of alkenes through aroyl radical addition/1,4-/1,2-Aryl shift cascade reactions
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UV light-mediated difunctionalization of alkenes through an aroyl radical addition/1,4-/1,2-aryl shift has been described. The resulted aroyl radical from a photocleavage reaction added to acrylamide compounds followed by cyclization led to the formation of oxindoles, whereas the addition to cinnamic amides aroused a unique 1,4-aryl shift reaction. Furthermore, the difunctionalization of alkenes of prop-2-en-1-ols was also achieved through aroyl radical addition and a sequential 1,2-aryl shift cascade reaction.
- Zheng, Lewei,Huang, Hongli,Yang, Chao,Xia, Wujiong
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supporting information
p. 1034 - 1037
(2015/03/30)
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- Metal-free nitro-carbocyclization of activated alkenes: A direct approach to synthesize oxindoles by cascade C-N and C-C bond formation
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A novel and direct metal-free nitro-carbocyclization of activated alkenes leading to valuable nitro-containing oxindoles via cascade C-N and C-C bond formation has been developed. The mechanistic study indicates that the initial NO and NO2 radical addition and the following C-H functionalization processes are involved in this transformation. The Royal Society of Chemistry 2014.
- Shen, Tao,Yuan, Yizhi,Jiao, Ning
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supporting information
p. 554 - 556
(2014/01/06)
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- Iron-catalyzed aerobic difunctionalization of alkenes: A highly efficient approach to construct oxindoles by C-S and C-C bond formation
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A novel iron-catalyzed efficient approach to construct sulfone-containing oxindoles, which play important roles in the structural library design and drug discovery, has been developed. The use of readily available benzenesulfinic acids, an inexpensive iron salt as the catalyst, and air as the oxidant makes this sulfur incorporation protocol very efficient and practical. This journal is the Partner Organisations 2014.
- Shen, Tao,Yuan, Yizhi,Song, Song,Jiao, Ning
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supporting information
p. 4115 - 4118
(2014/04/03)
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- The carbomethylation of arylacrylamides leading to 3-ethyl-3-substituted indolin-2-one by cascade radical addition/cyclization
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An FeCl2-promoted carbomethylation of arylacrylamides by di-tert-butyl peroxide (DTBP) is achieved, leading to 3-ethyl-3-substituted indolin-2-one in high yield. The reaction tolerates a series of functional groups, such as cyano, nitro, ethyloxy carbonyl, bromo, chloro, and trifluoromethyl groups. The radical methylation and arylation of the alkenyl group are involved in this reaction. This journal is the Partner Organisations 2014.
- Dai, Qiang,Yu, Jintao,Jiang, Yan,Guo, Songjin,Yang, Haitao,Cheng, Jiang
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supporting information
p. 3865 - 3867
(2014/04/03)
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- Synthesis of oxindoles through silver-catalyzed trifluoromethylation-, difluoromethylation- and arylsulfonylation-cyclization reaction of N-arylacrylamides
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Efficient synthesis of trifluoromethyl and difluoromethyl-substituted oxindoles was achieved by reacting Langlois reagent or Baran reagent with N-arylacrylamides. However, the reaction of aryl sulfinic acid sodium salts with N-arylacrylamides did not give the desulfinative products, instead, aryl sulfonated products were produced. Copyright
- Liu, Jidan,Zhuang, Shaobo,Gui, Qingwen,Chen, Xiang,Yang, Zhiyong,Tan, Ze
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supporting information
p. 3196 - 3202
(2014/06/09)
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- Catalyst-free direct arylsulfonylation of N-arylacrylamides with sulfinic acids: A convenient and efficient route to sulfonated oxindoles
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A simple, efficient and catalyst-free procedure has been developed for the construction of sulfonated oxindoles via the direct arylsulfonylation of N-arylacrylamides with sulfinic acids. The present protocol, which simply utilizes cheap oxidants, readily-available starting materials, and catalyst-free conditions, provides an alternative and highly attractive approach to a series of sulfonated oxindoles with high atom efficiency and excellent functional group tolerance. This journal is the Partner Organisations 2014.
- Wei, Wei,Wen, Jiangwei,Yang, Daoshan,Du, Juan,You, Jinmao,Wang, Hua
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supporting information
p. 2988 - 2991
(2014/06/10)
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- Arylnitration of alkenes by nitration/C-H functionalization cascade using AgNO3 and HOAc
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A novel arylnitration of alkenes by nitration and C-H functionalization cascade process has been developed. This methodology provides an efficient way to construct a variety of nitro-containing oxindoles and dihydroquinolin-2(1H)-ones. In addition, the process exhibits significant functional group tolerance. Moreover, the use of inexpensive and readily available starting materials makes this practical and atom-economical approach particularly attractive.
- Li, Ya-Min,Shen, Yuehai,Chang, Kwen-Jen,Yang, Shang-Dong
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supporting information
p. 2119 - 2122
(2015/03/18)
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- Direct annulations toward phosphorylated oxindoles: Silver-catalyzed carbon-phosphorus functionalization of alkenes
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Silver screen: The AgNO3-catalyzed carbon phosphorylation of alkenes occurs by an alkene addition/cyclization cascade. Ag+ reacts with Ph2P(O)H to form the crucial active intermediate 1, which promotes the reaction. This method requires a cheap, nontoxic silver salt as the catalyst and substrates for the transformation are simple and readily accessible.
- Li, Ya-Min,Sun, Meng,Wang, Hong-Li,Tian, Qiu-Ping,Yang, Shang-Dong
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supporting information
p. 3972 - 3976
(2013/05/09)
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- Metal-free carbonitration of alkenes using K2S2O 8
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A novel metal-free oxidative carbonitration of alkenes by a nitration and C-H functionalization cascade process has been developed. This methodology provides an efficient way to construct valuable nitro-containing oxindoles.
- Li, Ya-Min,Wei, Xiao-Hong,Li, Xi-An,Yang, Shang-Dong
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supporting information
p. 11701 - 11703
(2013/12/04)
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- Ruthenium- and rhodium-catalyzed cross-coupling reaction of acrylamides with alkenes: Efficient access to (Z,E)-dienamides
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Ruthenium- and rhodium-catalyzed direct oxidative cross-coupling reactions of acrylamides with alkenes were developed. These methods provide an efficient route for the synthesis of (Z,E)-dienamides in excellent yields with good stereoselectivity. The catalytic systems allowed oxidative olefination of a wide range of alkenes bearing different functional groups, such as CO2R, COMe, SO2Ph, aryl, CONHBn, CN, PO(OEt)2, as well as Weinreb amide.
- Zhang, Jian,Loh, Teck-Peng
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supporting information
p. 11232 - 11234
(2013/01/15)
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- Palladium-catalyzed oxidative aryltrifluoromethylation of activated alkenes at room temperature
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A palladium-catalyzed intramolecular oxidative aryltrifluoromethylation reaction of activated alkenes has been explored. The reaction allows for an efficient synthesis of a variety of CF3-containing oxindoles. Preliminary mechanistic study indicated that the reaction involves a Csp 3-PdIV(CF3) intermediate, which undergoes reductive elimination to afford a Csp3-CF3 bond.
- Mu, Xin,Wu, Tao,Wang, Hao-Yang,Guo, Yin-Long,Liu, Guosheng
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supporting information; experimental part
p. 878 - 881
(2012/02/17)
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- Metal-free synthesis of 3,3-disubstituted oxoindoles by iodine(III)-catalyzed bromocarbocyclizations
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"I" did it: An iodine(III)-mediated bromocarbocyclization was elaborated as an efficient tool for the synthesis of oxoindoles. This method is applicable to a variety of structurally different substrates, also with chemically sensitive groups, and gives access to the heterocycles in a regio- and stereoselective fashion (see scheme). The indole-2-ones obtained can be converted easily into structurally complex target compounds, such as the alkaloid physostigmine. Copyright
- Fabry, David C.,Stodulski, MacIej,Hoerner, Stefanie,Gulder, Tanja
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supporting information; experimental part
p. 10834 - 10838
(2012/09/10)
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- Ruthenium-catalyzed oxidative synthesis of 2-pyridones through C-H/N-H bond functionalizations
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An inexpensive ruthenium catalyst enabled oxidative annulations of alkynes by acrylamides with ample scope, which allowed for the preparation of 2-pyridones employing various electron-rich and electron-deficient acrylamides as well as (di)aryl- and (di)alkyl-substituted alkynes.
- Ackermann, Lutz,Lygin, Alexander V.,Hofmann, Nora
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supporting information; experimental part
p. 3278 - 3281
(2011/08/06)
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- Palladium-catalyzed oxidative arylalkylation of activated alkenes: Dual C-H bond cleavage of an arene and acetonitrile
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Not one but two: The title reaction proceeds through the dual C-H bond cleavage of both aniline and acetonitrile (see scheme). The reaction affords a variety of cyano-bearing indolinones in excellent yield. Mechanistic studies demonstrate that this reaction involves a fast arylation of the olefin and a rate-determining C-H activation of the acetonitrile. Copyright
- Wu, Tao,Mu, Xin,Liu, Guosheng
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supporting information; scheme or table
p. 12578 - 12581
(2012/02/04)
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- Catalytic dicyanative 5-exo- And 6-endo-cyclization triggered by cyanopalladation of alkynes
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A stereoselective dicyanative 5-exo- and 6endo-cyclization using various enynes has been investigated. The mode of cyclization is critically controlled by the structure of the substrates. For example, N-allyl derivatives prefer 5-exo-cyclization, while methacryloyl amides are transformed to the corresponding lactams with tetra substituted carbons at the alpha-position via 6-endo-cyclization. Both reactions include syn-cyanopalladation to carbon≡carbon triple bonds in the initial step, and sequential cyclization followed by reductive elimination in one operation enables the construction of the highly functionalized nitrogen heterocycles. The scope of suitable substrates and a proposed mechanism are also described.
- Arai, Shigeru,Koike, Yuka,Nishida, Atsushi
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experimental part
p. 893 - 900
(2010/07/06)
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- Palladium-catalyzed silane/siloxane reductions in the one-pot conversion of nitro compounds into their amines, hydroxylamines, amides, sulfonamides, and carbamates
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A combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS) facilitates the room-temperature reduction of aromatic nitro compounds to anilines. These reactions tend to be quick (30 min), high-yielding, and tolerate a range of other functional groups. Replacement of PMHS/KF with triethylsilane allows for the reduction of aliphatic nitro compounds to their corresponding hydroxylamines. Depending on the substrate, both conditions can allow for the in situ conversion of the product amines into amides, sulfonamides, and carbamates. Georg Thieme Verlag Stuttgart.
- Rahaim Jr., Ronald J.,Maleczka Jr., Robert E.
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p. 3316 - 3340
(2008/09/17)
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- Photochemical reactions of N-(2-halogenoalkanoyl) derivatives of anilines
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The photochemical reactions of 2-substituted N-(2-halogenoalkanoyl) derivatives 1 of anilines and 5 of cyclic amines are described. Under irradiation, 2-bromo-2-methylpropananilides 1a-e undergo exclusively dehydrobromination to give N-aryl-2-methylprop-2-enamides (= methacrylanilides) 3a-e (Scheme 1 and Table 1). On irradiation of N-alkyl- and N-phenyl-substituted 2-bromo-2-methylpropananilides 1f-m, cyclization products, i.e. 1,3-dihydro-2H-indol-2-ones (= oxindoles) 2f-m and 3,4- dihydroquinolin-2(1H)-ones (= dihydrocarbostyrils) 4f-m, are obtained, besides 3f-m. On the other hand, irradiation of N-methyl-substituted 2- chloro-2-phenylacetanilides 1o-q and 2-chloroacetanilide 1r gives oxindoles 2o-r as the sole product, but in low yields (Scheme 3 and Table 2). The photocyclization of the corresponding N-phenyl derivatives 1s-v to oxindoles 2s-v proceeds smoothly. A plausible mechanism for the formation of the photoproducts is proposed (Scheme 4). Irradiation of N-(2-halogenoalkanoyl) derivatives of cyclic amines 5a-c yields the cyclization products, i.e. five- membered lactams 6a, b, and/or dehydrohalogenation products 7a,c and their cyclization products 8a,c, depending on the ring size of the amines (Scheme 5 and Table 3).
- Nishio, Takehiko,Asai, Hidenori,Miyazaki, Takenori
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p. 1475 - 1483
(2007/10/03)
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- Base-promoted Reactions of α-Halogeno-alkylanilides
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Hydride-promoted reactions of 2-halogeno-alkylcarboxanilides afford heterocyclic and acyclic condensation products, some of the latter compounds arising upon hydrolysis and/or rearrangement of the former ones.Competitive formation of dioxopiperazines versus oxazolidinone derivatives or their transformation products depends mainly upon the nature (primary, secondary or tertiary) of the halide moiety.Concurrent dehydrohalogenation of 2-bromo-isobutyranilides leads to unsaturated condensation products.
- Cavicchioni, Giorgio,Scrimin, Paolo,Veronese, Augusto C.,Balboni, Gianfranco,D'Angeli, Ferruccio
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p. 2969 - 2972
(2007/10/02)
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