- N -Tosyl-3-azacyclohexyne. Synthesis and chemistry of a strained cyclic ynamide
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The first synthesis of a strained six-membered cyclic ynamide is described. N-Tosyl-3-azacyclohexyne is generated via fluoride-promoted 1,2 elimination under conditions that allow trapping of the strained heterocyclic alkyne in a variety of addition, insertion, and [2 + 2], [3 + 2], and [4 + 2] cycloaddition reactions.
- Tlais, Sami F.,Danheiser, Rick L.
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- Simple preparation of 3-Aryl 2-piperidinones
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A very simple method for obtaining α-arylated N-protected 2-piperidinones in high yields is described. The use of ZnCl2, LiHMDS or s-BuLi as the base and Pd(dba)2 as the catalyst are the key factors.
- De Filippis, Arnault,Pardo, Domingo Gomez,Cossy, Janine
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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 Double-Annulation Strategy for the Synthesis of Unusual Fused Bis-Heterocycles
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A novel metal-free double-annulation cascade for the construction of unusual fused heterocyclic systems is described. This simple protocol enables the sequential assembly of two rings in one pot from two simple precursors. Acidic conditions promote the condensation and the intramolecular alkynyl Prins reaction of an enyne or arenyne alcohol with a cyclic hemiaminal to form a five-, six-, or seven-membered oxacycle followed by a seven-or eight-membered azacycle. In this transformation, chemical complexity is rapidly generated with the formation of three new bonds (one C-O, one C-C, and one C-N) in one synthetic operation. The strategy is modular and relatively general, providing access to a series of unique fused bicyclic scaffolds.
- Abdul-Rashed, Shukree,Alachouzos, Georgios,Brennessel, William W.,Frontier, Alison J.
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supporting information
p. 4350 - 4354
(2020/06/04)
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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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- 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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supporting information
p. 6228 - 6238
(2017/11/15)
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- Synthesis of aminopyrazoles from sydnones and ynamides
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Aminopyrazoles are prepared from readily accessible sydnones and sulfonyl ynamides using either a copper-mediated sydnone alkyne cycloaddition (CuSAC) or in situ generated strained cyclic ynamides.
- Wezeman,Comas-Barceló,Nieger,Harrity,Br?se
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supporting information
p. 1575 - 1579
(2017/02/23)
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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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- Catalytic Ring Expansion of Cyclic Hemiaminals for the Synthesis of Medium-Ring Lactams
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A mild and efficient intermolecular ring-expansion approach was developed for the synthesis of medium-ring lactams by using siloxy alkynes. Key to success is the suitable combination of a superior catalyst and an exceptional nitrogen-protecting group. Control experiments indicated that the reaction is remarkably selective toward the desired lactam formation, even with many possible non-productive pathways. Growth rings: A mild catalytic synthesis of medium-ring lactams through ring expansion of cyclic hemiaminals was developed. This synthetically useful method also gives insight into the reactivity of both siloxy alkynes and N-acyliminium analogues.
- Zhao, Wanxiang,Qian, Hui,Li, Zigang,Sun, Jianwei
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supporting information
p. 10005 - 10008
(2015/08/19)
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- Laccase/2,2,6,6-tetramethylpiperidinoxyl radical (TEMPO): An efficient catalytic system for selective oxidations of primary hydroxy and amino groups in aqueous and biphasic media
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Copper salts/2,2,6,6-tetramethylpiperidinoxyl radical (TEMPO) catalytic systems enable efficient aerobic oxidations of primary alcohols but they generally show a reduced reactivity in aqueous medium. Herein, we report an oxidative catalytic system composed of Trametes versicolor laccase and TEMPO, which is able to work in buffer solutions at room temperature using ambient air. Although this catalytic system displays great efficiency in aqueous systems, the addition of methyl tert-butyl ether allows the reduction of TEMPO loading, also enhancing the solubility of hydrophobic compounds. This practical methodology promotes the chemoselective aerobic oxidation of hydroxy or amino groups, leading to interesting organic derivatives such as aldehydes, lactones, hemiaminals or lactams.
- Díaz-Rodríguez, Alba,Martínez-Montero, Lía,Lavandera, Iván,Gotor, Vicente,Gotor-Fernández, Vicente
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supporting information
p. 2321 - 2329
(2014/07/21)
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- Catalytic asymmetric allylic alkylation of 3-arylated piperidin-2-ones
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The preparation of optically active lactams from 3-aryl-2-piperidinone is reported. The quaternary carbon stereocentres were formed using palladium-catalysed asymmetric allylic alkylation reactions. The resulting enantioenriched compounds are useful inter
- Michon, Christophe,Bethegnies, Aurelien,Capet, Frederic,Roussel, Pascal,De Filippis, Arnault,Gomez-Pardo, Domingo,Cossy, Janine,Agbossou-Niedercorn, Francine
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p. 4979 - 4985
(2013/08/23)
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- Biomimetic aerobic oxidation of amino alcohols to lactams
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The right path: N-Protected amino alcohols undergo aerobic and biomimetic oxidation to the corresponding lactams in the presence of a ruthenium catalyst and a combination of electron-transfer mediators under air (see scheme). The reaction was used for the synthesis of five-, six-, and seven-, membered lactams and showed good tolerance to a number of N-protecting groups. Copyright
- Babu, Beneesh P.,Endo, Yoshinori,Baeckvall, Jan-E.
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supporting information
p. 11524 - 11527,4
(2012/12/11)
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- NHC-Catalyzed intramolecular redox amidation for the synthesis of functionalized lactams
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A very efficient NHC-catalyzed lactamization reaction is reported. For most cases, the ring expansion reaction proceeds to cleanly furnish five- and six-membered N-Ts and N-Bn lactams, without the need for further purification. Evidence is presented suggesting a dual role for the stoichiometric base: (1) deprotonation of the triazolium precatalyst and (2) activation of the nitrogen leaving group through hydrogen bonding.
- Thai, Karen,Wang, Li,Dudding, Travis,Bilodeau, Francois,Gravel, Michel
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supporting information; experimental part
p. 5708 - 5711
(2011/03/19)
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- Exploration of the interrupted Fischer indolization reaction
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A convergent method to access the fused indoline ring system present in a multitude of bioactive molecules has been developed. The strategy involves the condensation of hydrazines with latent aldehydes to ultimately deliver indoline-containing products by way of an interrupted Fischer indolization sequence. The method is convergent, mild, operationally simple, broad in scope, and can be used to access enantioenriched products. In addition, our approach is amenable to the synthesis of furoindoline and pyrrolidinoindoline natural products as demonstrated by the concise formal total syntheses of physovenine and debromoflustramine B. The strategy will likely enable the synthesis of more complex targets such as the communesin alkaloids.
- Schammel, Alex W.,Boal, Ben W.,Zu, Liansuo,Mesganaw, Tehetena,Garg, Neil K.
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supporting information; experimental part
p. 4687 - 4695
(2010/08/06)
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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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experimental part
p. 3095 - 3098
(2010/08/07)
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- An interrupted fischer indolization approach toward fused indoline-containing natural products
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An efficient method to access the fused indoline ring system present in a multitude of bioactive molecules has been developed. The strategy involves the condensation of hydrazines with latent aldehydes to ultimately deliver indoline-containing products by way of an interrupted Fischer indolization sequence. Our studies show that the approach will likely be amenable to the synthesis of complex targets, such as the communesin natural products.
- Boal, Ben W.,Schammel, Alex W.,Garg, Neil K.
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supporting information; experimental part
p. 3458 - 3461
(2009/12/07)
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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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- Synthesis of functionalized 1-azaspirocyclic cyclopentanones using bronsted acid or N-bromosuccinimide promoted ring expansions
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Azaspirocyclic ring systems are present in a variety of alkaloids. Functionalized 1-azaspirocyclopentanones (6, 7, 11, 12) can be efficiently constructed through semipinacol ring expansion reactions of 2-(1- hydroxycyclobutyl)-p-toluenesulfonylenamides (4
- Dake, Gregory R.,Fenster, Michael D. B.,Hurley, Paul B.,Patrick, Brian O.
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p. 5668 - 5675
(2007/10/03)
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- Palladium-catalyzed α-arylation of N-protected 2-piperidinones
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A very simple method for obtaining α-arylated N-protected 2-piperidinones in high yield is described. The use of ZnCl2 and Pd(dba)2 and the nature of the base are the key factors.
- Filippis, Arnault de,Pardo, Domingo Gomez,Cossy, Janine
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p. 9756 - 9768
(2007/10/03)
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- Construction of Azaspirocyclic Ketones through α-Hydroxyiminium Ion or α-Siloxy Epoxide Semipinacol Rearrangements
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(matrix presented) method 1: R,R1=H, n=1 method 2: R=TMS, R1=OH, n=2 Semipinacol-type rearrangements to produce azaspirocyclic ketones are presented. The yields and stereoselectivities of these reactions range from 67-94% yield and 2
- Fenster, Michael D. B.,Patrick, Brian O.,Dake, Gregory R.
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p. 2109 - 2112
(2007/10/03)
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- Diels-Alder reactions of 5,6-dihydro-2(1H)-pyridones
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The Diels-Alder reaction of achiral 5,6-dihydro-2(1H)-pyridones 12a,b and enantiopure 5,6-dihydro-2(1H)-pyridones 16a,b with a variety of diversely substituted buta-1,3-dienes under thermal or catalytic conditions, to give partially reduced isoquinolones 18-33 and 35-37, is reported. (C) 2000 Elsevier Science Ltd.
- Casamitjana, Núria,López, Virginia,Jorge, Angela,Bosch, Joan,Molins, Elies,Roig, Anna
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p. 4027 - 4042
(2007/10/03)
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- 1,5-Hydrogen transfers from carbon to N-tributyltin substituted nitrogen
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1,5-H transfers from carbon to N-tributyltin substituted nitrogen proceeded smoothly and were much more efficient than 1,5-H transfers from carbon to ordinary nitrogen. 1,5-Tribuyltin group transfer from carbon to nitrogen and intramolecular addition of an aminyl radical to a nitrile group were also observed for the first time.
- Kim, Sunggak,Yeon, Kyu Man,Yoon, Kwang Sub
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p. 3919 - 3922
(2007/10/03)
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- ELECTROCHEMICAL STUDIES ON HALOAMIDES. PART IX. ω-BROMO-N-TOSYLALKANAMIDES
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The electrochemical behaviour of ω-bromo-N-tosylalkanamides 1a-d at a mercury cathode in N,N-dimethylformamide solutions containing tatraethylammonium perchlorate as supporting electrode has been investigated.The cleavage of the N-S bond turns out to be selective for bromotosylvaleramide 1a and butyramide 1b giving high yields of the corresponding N-unsubstituted lactams, 2-piperidone 6a and 2-pyrrolidone 6b, irrespective of the reaction conditions.It is suggested that ring closure occurs via intramolecular nucleophilic substitution of nitrogen anions formed by dissociative electron transfer from the electrode or acid-base reaction in the bulk of the solution.Bromotosylpropanamide 1c undergoes unselective breaking of both electroactive groups C-Br and N-S and a mixture of products arising from their cleavage is formed.By way of contrast, bromotosylacetamide 1d undergoes selective cleavage of the C-Br bond giving, inter alia, its conjugate base whose stebility allowed us to further clarify the effect of added acids and bases on its voltammetric behaviour.
- Inesi, Achille,Casadei, Maria Antonietta,Moracci, Franco Micheletti,Jugelt, Werner
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- Synthesis of carbocyclic nucleosides from 2-azabicyclo[2.2.1]hept-5-en-3-ones: Sodium borohydride-mediated carbon-nitrogen bond cleavage of five- and six-membered lactams
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Various carbocyclic ribofuranosyl nucleosides were stereoselectively synthesized through a small number of steps from 2-azabicyclo[2.2.1]hept-5-en-3-ones by the use of sodium borohydride-mediated C-N bond cleavage as a key step. Ready availability of a no
- Katagiri,Muto,Nomura,Higashikawa,Kaneko
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p. 1112 - 1122
(2007/10/02)
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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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