- Dual Gold/Silver Catalysis: Indolizines from 2-Substituted Pyridine Derivatives via a Tandem C(sp3)–H Alkynylation/Iminoauration
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A dual gold/silver-catalyzed cascade C(sp3)–H alkynylation/iminoauration of 2-substituted pyridines with hypervalent iodine(III) reagents for the synthesis of indolizines is described. This novel reaction involves the formation of an alkynyl Au(III) species, a dual gold/silver-catalyzed C(sp3)–H functionalization, and a subsequent iminoauration process. A number of indolizines bearing diverse functionalities were prepared in good to excellent yield. Furthermore, a gram-scale reaction was efficiently conducted.
- Han, Chunyu,Liu, Yaowen,Tian, Xianhai,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 9480 - 9484
(2021/12/17)
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- Copper-Catalyzed Ullmann-Type Coupling and Decarboxylation Cascade of Arylhalides with Malonates to Access α-Aryl Esters
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We have developed a high-efficiency and practical Cu-catalyzed cross-coupling to directly construct versatile α-aryl-esters by utilizing readily available aryl bromides (or chlorides) and malonates. These gram-scale approaches occur with turnovers of up to 1560 and are smoothly conducted by the usage of a low catalyst loading, a new available ligand, and a green solvent. A variety of functional groups are tolerated, and the application occurs with α-aryl-esters to access nonsteroidal anti-inflammatory drugs (NSAIDs) on the gram scale.
- Chen, Fen-Er,Chen, Tao,Cheng, Fei,Huang, Yin-Qiu,Li, Jia-Wei,Xiao, Xiao,Zhou, Chen
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supporting information
(2022/01/04)
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- Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide-Functionalized Phosphine Ligands
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The coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α-aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide-functionalized phosphines to fit the requirements of Negishi couplings. Record-setting activities were achieved in palladium-catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl-YPhos ligand bearing an ortho-tolyl-substituent in the backbone. This highly electron-rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
- Hu, Zhiyong,Wei, Xiao-Jing,Handelmann, Jens,Seitz, Ann-Katrin,Rodstein, Ilja,Gessner, Viktoria H.,Goo?en, Lukas J.
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supporting information
p. 6778 - 6783
(2021/02/01)
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- Catalyst-Free Annulation of 2-Pyridylacetates and Ynals with Molecular Oxygen: An Access to 3-Acylated Indolizines
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A catalyst and additive-free annulation of 2-pyridylacetates and ynals under molecular oxygen was the first developed, affording 3-acylated indolizines in good to excellent yields. Molecular oxygen was used as the source of the carbonyl oxygen atom in indolizines. This approach was compatible with a wide range of functional groups, and especially it has been successfully extended to unsaturated double bonds and triple bonds, which were difficult to prepare by previous methods in a single step.
- Chen, Zhengwang,Liang, Pei,Ma, Xiaoyue,Luo, Haiqing,Xu, Guohai,Liu, Tanggao,Wen, Xiaowei,Zheng, Jing,Ye, Hui
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supporting information
p. 1630 - 1639
(2019/01/26)
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- A One-Pot Sonogashira Coupling and Annulation Reaction: An Efficient Route toward 4 H -Quinolizin-4-ones
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An efficient one-pot Sonogashira coupling and annulation reaction affording 4 H -quinolizin-4-ones in moderate to excellent yields is described. A variety of substituted iodoarenes and 2-alkylazaarenes were well tolerated, and especially the unsaturated double and triple bonds were compatible under the standard conditions.
- Chen, Zhengwang,Liu, Tanggao,Ma, Xiaoyue,Liang, Pei,Long, Lipeng,Ye, Min
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supporting information
p. 863 - 867
(2019/04/25)
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- One-Pot Regiospecific Synthesis of Indolizines: A Solvent-Free, Metal-Free, Three-Component Reaction of 2-(Pyridin-2-yl)acetates, Ynals, and Alcohols or Thiols
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A novel approach for the synthesis of indolizines from 2-(pyridin-2-yl)acetates, ynals, and alcohols or thiols has been developed. This MCR (multicomponent reaction) that proceeds under the solvent- and metal-free conditions has provided a straightforward path to construct indolizines. Furthermore, this reaction demonstrates other attractive features such as widely available starting materials, mild conditions, good functional group tolerance, and high efficiency.
- Yang, Daji,Yu, Yue,Wu, Yuanheng,Feng, Huiyi,Li, Xuechen,Cao, Hua
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supporting information
p. 2477 - 2480
(2018/04/25)
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- Revisiting the sparteine surrogate: Development of a resolution route to the (-)-sparteine surrogate
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The improved performance of the sparteine surrogate compared to sparteine in a range of applications has highlighted the need to develop an approach to the (-)-sparteine surrogate, previously inaccessible in gram-quantities. A multi-gram scale, chromatography-free synthesis of the racemic sparteine surrogate and its resolution via diastereomeric salt formation with (-)-O,O′-di-p-toluoyl-l-tartaric acid is reported. Resolution on a 10.0 mmol scale gave the diastereomeric salts in 33% yield from which (-)-sparteine surrogate of 937 er was generated. This work solves a key limitation: either enantiomer of the sparteine surrogate can now be readily accessed.
- Firth, James D.,O'Brien, Peter,Ferris, Leigh
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p. 9357 - 9365
(2015/01/16)
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- Cu(I)Br-mediated preparation of 14C-labeled 3-pyridine-acetate derivatives and synthesis of a novel 14C-labeled PDE-IV inhibitor
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An efficient protocol for the synthesis of 14C-labeled 3-pyridineacetate (1) and its N-oxide ([14C]2) is described. Oxidation of this pyridine ([14C]1) to its N-oxide ([ 14C]2) proceeded in high yield using H2O2 with MeReO3 as a catalyst. The reaction employs readily available diethyl [2-14C]malonate. This method has proven to be general in preparation of other pyridineacetate derivatives and their N-oxides which have been typically difficult to prepare by other means. Our development of the Cu(I)Br-coupling methodology as well as application to the synthesis of a 14C-labeled phosphodiesterase-IV (PDE-IV) inhibitor, [ 14C]3, are also reported. Copyright
- Ho, Jonathan Z.,Braun, Matthew P.
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p. 277 - 280
(2008/02/08)
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- 1,2-disubstituted-6-oxo-3-phenyl-piperidine-3-carboxamides and combinatorial libraries thereof
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The invention relates to combinatorial libraries containing two or more novel piperidine-3-carboxamide derivative compounds, methods of preparing the piperidine-3-carboxamide derivative compounds and piperidine-3-carboxamide derivative compounds bound to a resin
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- A novel decarbonylation of heterocyclic pyruvic acid derivatives using sodium perborate
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Decarbonylation of imidazo-2-yl and pyrid-2-ylpyruvic acids giving the corresponding acetic acids has been achieved using aqueous sodium perborate at room temperature. It is proposed that intramolecular hydrogen bonding, which inhibits conventional decarbonylation, facilitates epoxidation and subsequent decarboxylation of the enol tautomers.
- Ramsden, Christopher A.,Sargent, Bruce J.,Walle, Christiaan D.
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p. 1901 - 1904
(2007/10/03)
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- Synthesis of ethoxyethynylarenes by the palladium-catalyzed reaction of aryl iodides with ethoxy(trialkylstannyl)acetylenes
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Palladium-catalyzed reaction of aryl and heteroaryl iodides with ethoxy(trialkylstannyl)acetylenes gave the ethoxyethynylarenes and -heteroarenes, which were easily transformed by hydration reaction into ethyl areneacetates and heteroareneacetates.
- Sakamoto,Yasuhara,Kondo,Yamanaka
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p. 2032 - 2035
(2007/10/02)
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- HETARYLATION OF C-NUCLEOPHILES: A NEW COURSE FOR THE REACTION OF N-FLUOROPYRIDINIUM SALTS WITH CARBANIONS.
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The N-fluoropyridinium tetrafluoroborate reactions with carbanions were found either to follow the cine -(tele)-AEa-substitution or go through possible formation of a carbenic (cationic) intermediate; as a result 2- or 4-pyridyl derivatives are formed.
- Gakh, Andrei A.,Kiselyov, Alexander S.,Semenov, Victor V.
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p. 7379 - 7382
(2007/10/02)
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- Studies on Pyrimidine Derivatives. XXXVIII. Cross-Coupling Reaction of N-Heteroaryl Iodides with Ethoxycarbonylmethylzinc Bromide in the Presence of Palladium Catalyst
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In the presence of tetrakis(triphenylphosphine)palladium, 2-iodo-4,6-dimethylpyrimidine and 4-iodo-2,6-dimethylpyrimidine reacted with ethoxycarbonylmethylzinc bromide (Reformatsky reagent) to give ethyl 4,6-dimethyl-2-pyrimidineacetate and ethyl 2,6-dimethyl-4-pyrimidineacetate, respectively.In contrast, the reaction of 5-iodo-2,4-dimethylpyrimidine with the same reagent resulted in recovery of the starting iodide.Similar results were observed in the reactions of various N-heteroaryl iodides.Keywords - Reformatsky reagent; cross-coupling reaction; N-heteroaryl halide; N-heteroarylacetic acid; palladium catalyst; ethyl bromoacetate
- Yamanaka, Hiroshi,An-naka, Masayuki,Kondo, Yoshinori,Sakamoto, Takao
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p. 4309 - 4313
(2007/10/02)
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- REGIOSELECTIVE ADDITION OF TITANIUM ENOLATES TO 1-ACYLPYRIDINIUM SALTS. A CONVENIENT SYNTHESIS OF 4-(2-OXOALKYL)PYRIDINES
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Titanium enolates add to the 4-position of 1-phenoxycarbonylpyridinium salts to give 1,4-dihydropyridines; subsequent aromatization provides 4-(2-oxoalkyl)pyridines.
- Comins, Daniel L.,Brown, Jack D.
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p. 3297 - 3300
(2007/10/02)
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