- A Radical-Initiated Fragmentary Rearrangement Cascade of Ene-Ynamides to [1,2]-Annulated Indoles via Site-Selective Cyclization
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Straightforward access to [1,2]-annulated indoles, key substructures in natural products, is highly desirable yet challenging. Herein, a radical triggered fragmentary cyclization cascade reaction of ene-ynamides is presented, providing a rapid access into [1,2]-annulated indoles by an intermolecular radical addition, intramolecular cyclization, desulfonylative aryl migration, and site-selective C(sp2)-N cyclization sequence. DFT calculations support oxidation of N-centered radical species to cations prior to the C-N bond formation, followed by an unusual aza-Nazarov cyclization.
- Li, Sifan,Wang, Yu,Wu, Zibo,Shi, Weiliang,Lei, Yibo,Davies, Paul W.,Shu, Wei
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p. 7209 - 7214
(2021/09/14)
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- Pd-Catalyzed Indole Synthesis via C-H Activation and Bisamination Sequence with Diaziridinone
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This work describes an efficient Pd-catalyzed indole synthesis. A wide variety of indoles can be obtained in good yields from readily available vinyl bromides. The reaction likely proceeds through a sequential aryl C-H activation and bisamination of a resulting pallada(II)cycle with diaziridinone.
- Wang, Jianjun,Sun, Xiaofeng,Hu, Daguo,Shi, Yian
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supporting information
p. 7561 - 7565
(2021/10/02)
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- N -tert-butyl -2 -phenylindole derivative Preparation method and application
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The invention belongs to the technical field of organic synthesis, and particularly relates to N - tert-butyl -2 -phenyl indole derivatives as well as a preparation method and application thereof. The preparation method comprises the following steps: (Z)-1 - bromo -1 - phenyl -2 - styrene derivative, N, N - di-tert-butyl diazepinone, palladium catalyst, monophosphine ligand, hydrocarbon activator, base and first solvent, and N -tert-butyl -2 -aryl indole derivatives which can synthesize substituent type diversity, and the prepared N -tert-butyl -2 -aryl indole derivative can be used for preparing biologically active molecules N -2 .
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Paragraph 0217-0221
(2021/11/26)
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- Visible-Light-Induced Alkynylation of α-C–H Bonds of Ethers with Alkynyl Bromides without External Photocatalyst
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A direct alkynylation of C(sp3)–H bonds adjacent to an oxygen atom of ethers under visible light irradiation was developed in the absence of an external photocatalyst. The reaction of ethers and alkynyl bromides underwent smoothly to generate the corresponding products in good yields with excellent functional-group tolerance. Initial mechanistic experimental results indicated that the reaction may involve a free radical pathway.
- Xie, Xiaofei,Liu, Jie,Wang, Lei,Wang, Min
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p. 1534 - 1538
(2019/09/06)
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- The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
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Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
- Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
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supporting information
(2019/12/05)
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- Cs2CO3-Mediated Vicinal Thiosulfonylation of 1,1-Dibromo-1-Alkenes with Thiosulfonates: An Expedient Synthesis of (E)-1,2-Thiosulfonylethenes
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A new and highly efficient vicinal thiosulfonylation of 1,1-dibromo-1-alkenes with thiosulfonates in the presence of cesium carbonate has been developed. The metal-free diheterofunctionalization is an operationally simple to access a wide range of (E)-1,2-thiosulfonylethenes (α-aryl-β-thioarylvinyl sulfones) in moderate to high yields with high levels of stereoselectivities. Further, scalable reactions have been demonstrated for this transformation, thus illustrating its efficiency and practicality. (Figure presented.).
- Reddy, Raju Jannapu,Kumari, Arram Haritha,Kumar, Jangam Jagadesh,Nanubolu, Jagadeesh Babu
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supporting information
p. 1587 - 1591
(2019/02/16)
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- Construction of Phenanthrenes and Chrysenes from β-Bromovinylarenes via Aryne Diels-Alder Reaction/Aromatization
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A highly efficient transition-metal-free general method for the synthesis of polycyclic aromatic hydrocarbons like phenanthrenes and chrysenes (and tetraphene) from β-bromovinylarenes and arynes has been developed. The reactions proceed via an aryne Diels-Alder (ADA) reaction, followed by a facile aromatization. This is the first report on direct construction of chrysenes (and tetraphene) using the ADA approach. Unlike the literature method which is limited to only 9/10-substituted derivatives, this method gives access to a wide variety of functionalized phenanthrenes.
- Singh, Vikram,Verma, Ram Subhawan,Khatana, Anil K.,Tiwari, Bhoopendra
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supporting information
p. 14161 - 14167
(2019/10/28)
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- Visible Light-Catalyzed Decarboxylative Alkynylation of Arenediazonium Salts with Alkynyl Carboxylic Acids: Direct Access to Aryl Alkynes by Organic Photoredox Catalysis
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A convenient method mediated by photoredox catalysis is developed for the direct construction of aryl alkynes. Readily available aromatic diazonium salts have been utilized as the aryl radical source to couple alkynyl carboxylic acids to feature the decarboxylative arylation. A wide range of substrates are amenable to this protocol with broad functional group tolerance, and diversely-functionalized aryl alkynes could be synthesized under mild, neutral and transition metal-free reaction conditions using visible light irradiation. Alongside synthetic sustainability associated with the photocatalytic and transition metal-free operation, another key point of this method is that the organic dye catalyst acts as an excited-state reductant, thus establishing the quenching cycle for radical addition and decarboxylative elimination. (Figure presented.).
- Yang, Liangfeng,Li, Haifeng,Du, Yijun,Cheng, Kai,Qi, Chenze
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p. 5030 - 5041
(2019/11/03)
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- PHOTOISOMERIZABLE DIPHENYLDIACETYLENE-AZOBENZEN MESOGENS AND POLYMERS THERE OF
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The present invention relates to an azobenzene compound, a hologram recording composition containing the same, a hologram recording medium, a hologram recording material using the same, and a hologram recording or rewriting method. The azobenzene monomer
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Paragraph 0181; 0182
(2018/08/02)
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- PYRROLE DERIVATIVES AS PLK1 INHIBITORS
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The invention provides compounds of the formula (3): or a pharmaceutically acceptable salt or tautomer thereof. The compounds are useful in the treatment of cancers.
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Page/Page column 131; 132
(2018/11/22)
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- A Highly Reduced Ni-Li-Olefin Complex for Catalytic Kumada-Corriu Cross-Couplings
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The catalytic activity of a highly reduced Ni catalyst in the context of a Kumada-Corriu cross-coupling has been studied. This nickel complex is characterized by its high electron density, stabilized by simple olefin ligands in combination with two Li ions. Landmark reactivity has been found with this precatalyst which operates at cryogenic temperatures, thus allowing the presence of sensitive functionalities. Structural elucidation of oxidative addition intermediates and their reactivity suggest highly reduced species being operative in the C-C bond forming event.
- Nattmann, Lukas,Lutz, Sigrid,Ortsack, Pascal,Goddard, Richard,Cornella, Josep
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supporting information
p. 13628 - 13633
(2018/10/24)
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- Nickel-Catalyzed Enantioselective Cross-Coupling of N-Hydroxyphthalimide Esters with Vinyl Bromides
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An enantioselective Ni-catalyzed cross-coupling of N-hydroxyphthalimide esters with vinyl bromides is reported. The reaction proceeds under mild conditions and uses tetrakis(N,N-dimethylamino)ethylene as a terminal organic reductant. Good functional group tolerance is demonstrated, with over 20 examples of reactions that proceed with >90% ee.
- Suzuki, Naoyuki,Hofstra, Julie L.,Poremba, Kelsey E.,Reisman, Sarah E.
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supporting information
p. 2150 - 2153
(2017/04/27)
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- Synthesis of Ketones and Esters from Heteroatom-Functionalized Alkenes by Cobalt-Mediated Hydrogen Atom Transfer
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Cobalt bis(acetylacetonate) is shown to mediate hydrogen atom transfer to a broad range of functionalized alkenes; in situ oxidation of the resulting alkylradical intermediates, followed by hydrolysis, provides expedient access to ketones and esters. By modification of the alcohol solvent, different alkyl ester products may be obtained. The method is compatible with a number of functional groups including alkenyl halides, sulfides, triflates, and phosphonates and provides a mild and practical alternative to the Tamao-Fleming oxidation of vinylsilanes and the Arndt-Eistert homologation.
- Ma, Xiaoshen,Herzon, Seth B.
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p. 8673 - 8695
(2016/10/17)
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- Direct Alkynylation of 3H-Imidazo[4,5-b]pyridines Using gem-Dibromoalkenes as Alkynes Source
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C2 direct alkynylation of 3H-imidazo[4,5-b]pyridine derivatives is explored for the first time. Stable and readily available 1,1-dibromo-1-alkenes, electrophilic alkyne precursors, are used as coupling partners. The simple reaction conditions include an inexpensive copper catalyst (CuBr·SMe2 or Cu(OAc)2), a phosphine ligand (DPEphos) and a base (LiOtBu) in 1,4-dioxane at 120 °C. This C-H alkynylation method revealed to be compatible with a variety of substitutions on both coupling partners: heteroarenes and gem-dibromoalkenes. This protocol allows the straightforward synthesis of various 2-alkynyl-3H-imidazo[4,5-b]pyridines, a valuable scaffold in drug design.
- Aziz, Jessy,Baladi, Tom,Piguel, Sandrine
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p. 4122 - 4133
(2016/06/09)
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- The Dual Role of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) in the Synthesis of Terminal Aryl- and Styryl-Acetylenes via Umpolung Reactivity
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The dual role of the bicyclic amidine base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was demonstrated in a synthesis of terminal aryl- and styryl-acetylenes. Mechanistically, a tandem process involving elimination/Umpolung/protonation occurs in a single step to generate terminal aryl- and styryl-acetylenes from geminal dibromoalkenes. The key to the success of this transformation lies in the organobase-mediated generation of the acetylide from the 1-bromoalkynes at room temperature. The unique characteristics of DBU as an inherently safer reagent make it an attractive alternative to previous systems wherein required pyrophoric reagents and nonambient temperatures remain unsolved issues. The procedure does not work for the synthesis of alkyl-acetylenes.
- Morri, Ashok Kumar,Thummala, Yadagiri,Doddi, Venkata Ramana
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supporting information
p. 4640 - 4643
(2015/09/28)
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- The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow
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The application of a monolithic form of triphenylphosphine to the Ramirez gem-dibromoolefination reaction using flow chemistry techniques is reported. A variety of gem-dibromides were synthesised in high purity and excellent yield following only removal of solvent and no further off-line purification. It is also possible to perform the Appel reaction using the same monolith and the relationship between the mechanisms of the two reactions is discussed.
- Roper, Kimberley A.,Berry, Malcolm B.,Ley, Steven V.
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supporting information
p. 1781 - 1790
(2013/10/22)
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- Nickel(II)-magnesium-catalyzed cross-coupling of 1,1-dibromo-1-alkenes with diphenylphosphine oxide: One-pot synthesis of (E)-1-alkenylphosphine oxides or bisphosphine oxides
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A novel nickel(II)-magnesium-mediated cross-coupling of diphenylphosphine oxide with a variety of 1,1-dibromo-1-alkenes has been developed, which provides a powerful and general methodology for the stereoselective synthesis of various (E)-1-alkenylphosphine oxides or bisphosphine oxides, with operational simplicity of the procedure, good to high yields and broad substrate applicability. Mechanistic studies reveal that the reaction might involve a Hirao reduction, cross-coupling and Michael addition. Copyright
- Liu, Liu,Wang, Yulei,Zeng, Zhiping,Xu, Pengxiang,Gao, Yuxing,Yin, Yingwu,Zhao, Yufen
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supporting information
p. 659 - 666
(2013/04/10)
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- Efficient synthesis of 1,3-diaryl-4-halo-1 H-pyrazoles from 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes
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An efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles was achieved. The synthesis involves the [3 + 2] dipolar cycloaddition of 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes. The process proceeds smoothly in moderate to excellent yields. 1,3-Diaryl-4-
- Yang, Yiwen,Kuang, Chunxiang,Jin, Hui,Yang, Qing,Zhang, Zhongkui
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supporting information; experimental part
p. 1656 - 1662
(2012/02/04)
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- Convenient synthesis of 2-aryl-1-haloindolizines from pyridinium salts and 2-aryl-1,1-dihaloalk-1-enes
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2-Aryl-1-haloindolizines were synthesized from pyridinium salts and 2-aryl-1,1-dihaloalk-1-enes using a DBU/THF system. 2-Aryl-1,1-dihaloalk-1-enes containing electron-withdrawing or -donating groups were efficiently converted into the corresponding 2-aryl-1-haloindolizines in moderate to excellent yields. Georg Thieme Verlag Stuttgart.
- Yang, Yiwen,Kuang, Chunxiang,Jin, Hui,Yang, Qing
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supporting information; experimental part
p. 3447 - 3452
(2011/12/04)
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- Pd-catalyzed domino synthesis of internal alkynes using triarylbismuths as multicoupling organometallic nucleophiles
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Figure presented The domino coupling reaction of 1,1-dibromo-1-alkenes with triarylbismuth nucleophiles has been demonstrated to furnish disubstituted alkynes directly under catalytic palladium conditions. The couplings of triarylbismuths as multicoupling nucleophiles with 3 equiv of 1,1-dibromo-1-alkenes are very fast, affording high yields of alkynes in a short reaction time. Thus, an efficient domino process has been accomplished using 1,1-dibromo-1-alkenes as surrogates for internal alkyne synthesis in couplings with triarylbismuths in a one-pot operation.
- Rao, Maddali L. N.,Jadhav, Deepak N.,Dasgupta, Priyabrata
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supporting information; experimental part
p. 2048 - 2051
(2010/07/03)
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- 1,1-dibromo-1-alkenes as valuable partners in the copper-catalyzed direct alkynylation of azoles
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The copper-catalyzed direct alkynylation of azoles with 1,1-dibromo-1-alkenes as electrophiles is described. These easily accessible substrates are a useful addition to the field of direct alkynylations in an efficient and functional group tolerant reaction to provide a straightforward entry to diverse alkynyl heterocycles.
- Pacheco Berciano, Beatriz,Lebrequier, Sabrina,Besselievre, Francois,Piguel, Sandrine
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supporting information; experimental part
p. 4038 - 4041
(2010/11/16)
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- Tetraarylphosphonium salts as solubility-control groups: Phosphonium-supported triphenylphosphine and azodicarboxylate reagents
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(Chemical Equation Presented) Predictable solubilities! Reagents supported on a tetraarylphosphonium group have solubilities that can be predicted. The reagents and their by-products can be readily removed, recovered, and recycled after reaction by a precipitation/filtration sequence initiated by the addition of a low-polarity solvent, such as diethyl ether. Furthermore, the supported reagents are robust and exhibit reactivities similar to their parent compounds.
- Poupon, Jean-Christophe,Boezio, Alessandro A.,Charette, Andre B.
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p. 1415 - 1420
(2007/10/03)
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- Efficient Synthesis of Biindenylidene Derivatives via a Domino-Heck-Type Double Cyclization of Diaryldienynes
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(Equation presented) Synthesis of aromatic ring substituted (E)-1,1′-biindenylidene derivatives was achieved by a domino-Heck type double cyclization of (Z,Z)-1,6-diaryl-1,5-hexadien-3-ynes.
- Abdur Rahman,Sonoda, Motohiro,Itahashi, Kayo,Tobe, Yoshito
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p. 3411 - 3414
(2007/10/03)
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- An efficient method for one-carbon elongation of aryl aldehydes via their dibromoalkene derivatives
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Various aryl aldehydes were efficiently converted into one-carbon extended aryl acetamides or aryl acetic acids through the reaction of their dibromoalkene derivatives with pyrrolidine in the presence of water under very mild conditions.
- Huh, Dal Ho,Jeong, Ji Sang,Lee, Hee Bong,Ryu, Hoejin,Kim, Young Gyu
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p. 9925 - 9932
(2007/10/03)
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- The Stille Reaction of 1,1-Dibromo-1-alkenes: Preparation of Trisubstituted Alkenes and Internal Alkynes
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The Stille reaction of 1,1-dibromo-1-alkenes 1 with aryl- and vinylstannanes produces different products depending on the reaction conditions. When the reaction is run in toluene or 1,4-dioxane with tris(2-furyl)phosphine (TFP) as the ligand, (Z)-bromoalkenes 2 are obtained stereospecifically in good to excellent yields with most substrates. However, 2-aryl-1,1-dibromo-1-alkenes (1e,1g) having an electron-donating methoxy group in the para- or ortho- position give poor yields. This method has been applied to the one-pot syntheses of stereospecifically trisubstituted alkenes 5. When the Stille reaction is conducted in a highly dipolar solvent (DMF), monobromides 2 and/or internal alkynes 4 are the products. The less reactive phenylstannane favors the formation of alkynes 4, regardless of which ligand is used. More reactive organostannanes (vinyl, furyl) require a very electron rich ligand, tris(4-methoxyphenyl)phosphine, for the formation of alkynes 4. This new method for internal alkyne preparation is general, requires very mild reaction conditions, and gives high yields.
- Shen, Wang,Wang, Le
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p. 8873 - 8879
(2007/10/03)
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- 3α-Hydroxy-3β-(phenylethynyl)-5β-pregnan-20-ones: Synthesis and pharmacological activity of neuroactive steroids with high affinity for GABA(A) receptors
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Neuroactive steroids that allosterically modulate GABA(A) receptors have potential uses as anticonvulsants, anxiolytics, and sedative-hypnotic agents. Recently, a series of pregnanes substituted with simple alkyl groups at the 3β-position were synthesized
- Upasani, Ravindra B.,Yang, Kevin C.,Acosta-Burruel, Manuel,Konkoy, Chris S.,McLellan, James A.,Woodward, Richard M.,Lan, Nancy C.,Carter, Richard B.,Hawkinson, Jon E.
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- Synthesis and Characterization of Liquid Crystalline Monomers and Side-Chain Polymers Containing Diphenyldiacetylene Mesogens
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Nine unsymmetrically diphenyldiacetylenic monomers were prepared.The phase behavior as well as thermal polymerization of the obtained monomers were characterized by optical polarizing microscopy and DSC measurement.UV absorption, refractive indices and dielectric constants of the monomers were also measured.The olefinic monomers were subjected to undergo hydrosilylation reaction with poly(methylhydrogensiloxane) to form the polysiloxanes.Thermal behavior of the prepared polysiloxanes were studied.
- Lu, Yong-Hong,Hsu, Chain-Shu,Wu, Shin-Tson
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