- A Gold(I)-Catalyzed Oxidative Rearrangement of Heterocycle-Derived 1,3-Enynes Provides an Efficient and Selective Route to Divinyl Ketones
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The gold-catalyzed oxidation of N-tosyl-protected 6-alkynyl-3,4-dihydro-2H-pyridines was studied in detail to obtain divinyl ketones in which one of the double bonds is embedded in a heterocyclic framework. The best reaction conditions were then extended
- Nejrotti, Stefano,Prina Cerai, Gabriele,Oppedisano, Alberto,Maranzana, Andrea,Occhiato, Ernesto G.,Scarpi, Dina,Deagostino, Annamaria,Prandi, Cristina
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- Transamidation for the Synthesis of Primary Amides at Room Temperature
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Various primary amides have been synthesized using the transamidation of various tertiary amides under metal-free and mild reaction conditions. When (NH4)2CO3 reacts with a tertiary amide bearing an N-electron-withdrawing substituent, such as sulfonyl and diacyl, in DMSO at 25 °C, the desired primary amide product is formed in good yield with good funcctional group tolerance. In addition, N-tosylated lactam derivatives afforded their corresponding N-tosylamido alkyl amide products via a ring opening reaction.
- Chen, Jiajia,Lee, Sunwoo,Xia, Yuanzhi
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supporting information
(2020/05/05)
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- One-Pot Reductive Allylation of Amides by Using a Combination of Titanium Hydride and an Allylzinc Reagent: Application to a Total Synthesis of (-)-Castoramine
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A one-pot direct reductive allylation protocol has been developed for the synthesis of secondary amines by using titanium hydride and an allylzinc reagent. This protocol is applicable to a broad range of substrates, including acyclic amides, benzamides, α,β-unsaturated amides, and lactams. The stereochemical outcome obtained from the reaction with crotylzinc reagent suggested that the allylation reaction proceeds through a six-membered cyclic transition state. A total synthesis of (-)-castoramine was accomplished by following this protocol for the highly stereoselective construction of contiguous stereocenters.
- Itabashi, Suguru,Shimomura, Masashi,Sato, Manabu,Azuma, Hiroki,Okano, Kentaro,Sakata, Juri,Tokuyama, Hidetoshi
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supporting information
p. 1786 - 1790
(2018/07/03)
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- Ruthenium-Pincer-Catalyzed Hydrogenation of Lactams to Amino Alcohols
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By using the commercially available ruthenium pincer complex (Ru-MACHO-BH) as a catalyst, the challenging direct hydrogenation of lactams and analogues has been successfully accomplished to deliver corresponding value-added amino alcohols in good-to-excellent yields under mild reaction conditions. Remarkably, in addition to N-protected lactams, unprotected ones could also be readily reduced in the presence of a catalytic amount of weak base or even under neutral reaction conditions, which further highlights the broad substrate scope and the protocol efficiency.
- Chen, Jiangbo,Wang, Jiaquan,Tu, Tao
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p. 2559 - 2565
(2018/07/30)
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- Synthesis of 2-carboxylated aza-ring derivatives through α-monohalogenation/ring-contraction of N-sulfonyl lactams
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2-Carboxylated aza-rings have been synthesized in two steps through a highly selective monohalogenation of N-sulfonylated lactams of various ring sizes (from 5- to 8-membered rings) followed by a ring contraction reaction. The selective monohalogenation of N-sulfonyl lactams has been achieved in modest to excellent yields (9 examples, 39–96%) using N-halogenosuccinimides via the in situ generation of trimethylsilyl ketene aminal derivatives. The so-obtained α-halogeno N-sulfonyl lactams were engaged in a ring opening/ring closing reaction in the presence of various alcohols or anilines under basic conditions affording 2-carboxylated aza-rings, such as azetidine, pyrrolidine or piperidine derivatives in high yields (24 examples, 61–99%).
- Sirindil, Fatih,Miaskiewicz, Solène,Kern, Nicolas,Lalaut, Arno,Felten, Anne-Sophie,Weibel, Jean-Marc,Pale, Patrick,Blanc, Aurélien
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supporting information
p. 5096 - 5106
(2017/07/28)
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- Gold(I)-Catalyzed N-Desulfonylative Amination versus N-to-O 1,5-Sulfonyl Migration: A Versatile Approach to 1-Azabicycloalkanes
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Valuable 1-azabicycloalkane derivatives have been synthesized through a novel gold(I)-catalyzed desulfonylative cyclization strategy. An ammoniumation reaction of ynones substituted at the 1-position with an N-sulfonyl azacycle took place in the presence of a gold cation by intramolecular cyclization of the disubstituted sulfonamide moiety onto the triple bond. Depending on the size of the heterocyclic ring and substitution of the substrates, two unprecedented forms of nucleophilic attack on the sulfonyl group were exploited, that is, a N-desulfonylation in the presence of an external protic O nucleophile (37–87 %, 10 examples) and a unique N-to-O 1,5-sulfonyl migration (60–98 %, 9 examples).
- Miaskiewicz, Solène,Gaillard, Boris,Kern, Nicolas,Weibel, Jean-Marc,Pale, Patrick,Blanc, Aurélien
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supporting information
p. 9088 - 9092
(2016/07/26)
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- Unusual skeletal rearrangement of unsaturated seven-membered lactams into fused pyrrolidinolactones
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Unsaturated ε-lactams undergo a novel process involving a skeletal reorganization to give fused pyrrolidine-lactones by reaction with aromatic α-bromo ketones in the presence of 1,4-diazabicyclo[2.2.2]octane and a base. The process involves the formation
- Alvarez, Silvia,Dominguez, Gema,Gradillas, Ana,Perez-Castells, Javier
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p. 3094 - 3102
(2013/06/27)
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- Nitrogen ylide-mediated cyclopropanation of lactams and lactones
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Cyclopropanation of α,β-unsaturated δ-lactams and δ-lactones mediated by nitrogen ylides is described. The process tolerates different alkyl halides and gives efficiently bicyclo[4.1.0]heptanes in a totally stereoselective manner. On the other hand, ε-lac
- Villar, Irene Suarez del,Gradillas, Ana,Domínguez, Gema,Pérez-Castells, Javier
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supporting information; experimental part
p. 3095 - 3098
(2010/08/07)
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- Hydrogenation of N-acylcarbamates and N-acylsulfonamides catalyzed by a bifunctional [Cp*Ru(PN)] complex
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Awakening of the Cp one: the bifunctional complex 1 facilitates the interaction with substrates bearing less electrophilic carbon atoms than ketones, epoxides, and imides. The title reaction was applicable to the reduction of Evans' asymmetric alkylation products to the chiral alcohols along with gtood recovery of the chiral oxazolidinone auxiliary. EWG=electron- withdrawing group.
- Ito, Masato,Koo, Lee Wei,Himizu, Akio,Kobayashi, Chika,Sakaguchi, Ayaka,Ikariya, Takao
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supporting information; experimental part
p. 1324 - 1327
(2009/06/30)
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- One-pot synthesis of benzothiazolines and napthathiazolines via cascade ortho-lithiation, cyclisation and elimination of N-arylsulfonyl lactams
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ortho-Lithiation of cyclic aryl sulfonamides in the presence of phosphoryl chloride provides a very simple entry to fused polycyclic sultams (benzothiazolines and naphthathiazolines). The Royal Society of Chemistry.
- Harling, John. D.,Steel, Patrick. G.,Woods, Tom. M.,Yufit, Dmitry S.
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p. 3472 - 3476
(2008/09/19)
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- A MILD AND EFFICIENT METHOD FOR THE PREPARATION OF N-TOSYL AMIDES AND LACTAMS
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N-tosyl amides and lactams can be prepared easily and under mild conditions by the inter- or intramolecular condensation of carboxylic acids and secondary sulfonamides.The coupling reagent used is dicyclohexylcarbodiimide (DCC) in the presence of 4-pyrrolidinopyridine (4-PPY) and the reactions proceed readily, usually in high yield, at room temperature.
- Tanner, David,Somfai, Peter
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p. 613 - 618
(2007/10/02)
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