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Aerobic Direct Dioxygenation of Terminal/Internal Alkynes to α-Hydroxyketones by an Fe Porphyrin Catalyst
We herein report a new synthetic method for the preparation of α-hydroxyketones by the dioxygenation of alkynes. The reaction proceeds at room temperature under the action of Fe porphyrin and pinacolborane under air as a green oxidant to produce α-hydroxyketones. The mild reaction conditions allow chemoselective oxidation with functional group tolerance. Terminal alkynes in addition to internal alkynes are applicable, affording unsymmetrical α-hydroxyketones that are difficult to obtain by any reported dioxygenation of unsaturated C?C bonds.
Kimura, Kento,Kurahashi, Takuya,Matsubara, Seijiro
supporting information
p. 3615 - 3618
(2021/10/01)

Method for efficiently synthesizing 1,6-diene-3-ketone derivatives
The invention discloses a method for efficiently synthesizing 1,6-diene-3-ketone derivatives, which comprises the following steps: in an organic solvent system, taking a compound represented by a formula 2 as a raw material, carrying out stirring reflux r
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Paragraph 0025-0026; 0033-0035

(2021/01/29)

Enantioselective nickel-catalyzedanti-arylmetallative cyclizations onto acyclic electron-deficient alkenes
Enantioselective nickel-catalyzed reactions of (hetero)arylboronic acids or alkenylboronic acids with substrates containing an alkyne tethered to various acyclic electron-deficient alkenes are described.
Gillbard, Simone M.,Green, Harley,Argent, Stephen P.,Lam, Hon Wai
supporting information
p. 4436 - 4439
(2021/05/10)

Electrochemically enabled rhodium-catalyzed [4 + 2] annulations of arenes with alkynes
Herein, electrochemically driven, Rh(iii)-catalyzed regioselective annulations of arenes with alkynes have been established. The strategy, combining the use of a rhodium catalyst with electricity, not only avoids the need for using a stoichiometric amount of external oxidant, but also ensures that the transformations proceed under mild and green conditions, which enable broad functional group compatibility with a variety of substrates, including drugs and pharmaceutical motifs. Moreover, the electrolysis reaction was made operationally simple by employing an undivided cell, and proceeds efficiently in aqueous solution in air. This journal is
Chen, Jia-Yi,Li, Ming,Li, Rui-Tao,Ma, Qiang,Ni, Shao-Fei,Wang, Zi-Chen,Wen, Li-Rong,Zhang, Lin-Bao
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p. 9515 - 9522
(2021/12/09)

Alkyne Aminopalladation/Heck and Suzuki Cascades: An Approach to Tetrasubstituted Enamines
Alkyne aminopalladation reactions starting from tosylamides are reported. The emerging vinylic Pd species are converted either in an intramolecular Heck reaction with olefinic units or in an intermolecular Suzuki reaction by using boronic acids exhibiting broad functional group tolerance. Tetra(hetero)substituted tosylated enamines are obtained in a simple one-pot process.
Geffers, Finn J.,Jones, Peter G.,Kurth, Florens R.,Werz, Daniel B.
supporting information
p. 14846 - 14850
(2021/10/19)

Palladium-Catalyzed Synthesis of Tricyclic Indoles via a N-S Bond Cleavage Strategy
In palladium/norbornene (Pd/NBE) chemistry, the "ortho effect"has been proven to be a key factor in the process of β-carbon elimination to extrude NBE. Herein, we found that the o-iodoaniline protected by a p-methoxybenzenesulfonyl group can recover the "
Zhang, Bo-Sheng,Wang, Fan,Gou, Xue-Ya,Yang, Ying-Hui,Jia, Wan-Yuan,Liang, Yong-Min,Wang, Xi-Cun,Li, Yuke,Quan, Zheng-Jun
supporting information
p. 7518 - 7523
(2021/10/01)

Sodium-metal-promoted reductive 1,2-syn-diboration of alkynes with reduction-resistant trimethoxyborane
Reductive 1,2-diboration of alkynes has been accomplished by means of sodium dispersion in the presence of trimethoxyborane as a reduction-resistant boron electrophile. Two boron moieties can be introduced onto alkynes with excellent syn selectivity to afford the corresponding (Z)-1,2-diborylalkenes. Bis(borate) species generated in situ can be involved in one-pot Suzuki-Miyaura arylation, formal arylboration of alkynes thus being executed.
Fukazawa, Mizuki,Ito, Shiori,Nogi, Keisuke,Takahashi, Fumiya,Yorimitsu, Hideki
p. 1171 - 1179
(2020/10/18)

Copper-Catalyzed Enantioselective Hydroalkoxylation of Alkenols for the Synthesis of Cyclic Ethers
The copper-catalyzed enantioselective intramolecular hydroalkoxylation of unactivated alkenes for the synthesis of tetrahydrofurans, phthalans, isochromans, and morpholines from 4- and 5-alkenols is reported. The substrate scope is complementary to existing enantioselective alkene hydroalkoxylations and is broad with respect to substrate backbone and alkene substitution. The asymmetric induction and isotopic labeling studies support a polar/radical mechanism involving enantioselective oxycupration followed by C-[Cu] homolysis and hydrogen atom transfer. Synthesis of the antifungal insecticide furametpyr was accomplished.
Chen, Dake,Berhane, Ilyas A.,Chemler, Sherry R.
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p. 7409 - 7414
(2020/06/29)

A Pd NP-confined novel covalent organic polymer for catalytic applications
A novel unsymmetrical covalent organic polymer, COP (1), was designed and characterized using several analytical and spectroscopic techniques. COP (1) was synthesized via the nucleophilic substitution reaction of 2,4,6-trichloro-1,3,5-triazine with p-amin
Yadav, Deepika,Awasthi, Satish Kumar
p. 1320 - 1325
(2020/02/04)

One-Pot Double-Annulation Strategy for the Synthesis of Unusual Fused Bis-Heterocycles
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.
supporting information
p. 4350 - 4354
(2020/06/04)

Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton-Coupled Electron Transfer
We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Br?nsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented.
Knowles, Robert R.,Metrano, Anthony J.,Tsuchiya, Yuto,Tsui, Elaine
supporting information
p. 11845 - 11849
(2020/05/22)

Tetrahydroxydiboron-Promoted Radical Addition of Alkynols
Tetrahydroxydiboron has previously been used as a borylation or reducing reagent in organic synthesis. Herein, we present a novel tetrahydroxydiboron-promoted radical addition of internal alkynes followed by intramolecular oxidation of alcohol through 1,5-hydrogen atom transfer. Preliminary mechanistic studies showed that the process might be initiated through N,N-dimethylformamide-assisted homolytic cleavage of tetrahydroxydiboron. This process provides a convenient synthesis of fluoroalkyl-substituted alkenes with a pendant aldehyde or ketone moiety.
Sun, Ze-Ying,Zhou, Sen,Yang, Kai,Guo, Minjie,Zhao, Wentao,Tang, Xiangyang,Wang, Guangwei
supporting information
p. 6214 - 6219
(2020/08/12)

Chemoselective Biohydrogenation of Alkenes in the Presence of Alkynes for the Homologation of 2-Alkynals/3-Alkyn-2-ones into 4-Alkynals/Alkynols
The chemoselective hydrogenation of alkenes in the presence of alkynes is a very challenging transformation to achieve with traditional chemical methods. The development of an effective procedure to perform this transformation would enrich the tool-kit available to organic chemists for the development of useful synthetic routes, and the creation of novel structural motifs. The reduction of activated alkene bonds by ene-reductases (ERs) is completely chemoselective, because of the mechanism of the reaction. Thus, we investigated the use of ERs belonging to the Old Yellow Enzyme family for the reduction of α,β-unsaturated aldehydes with a conjugated C≡C triple bond at the γ position. This reaction was exploited as the key step for the development of an effective homologation route to convert aryl and alkyl substituted propynals and butynones into 4-alkynals and 4-alkynols, avoiding some troublesome or hazardous steps of known synthetic routes. (Figure presented.).
Colombo, Danilo,Brenna, Elisabetta,Gatti, Francesco G.,Ghezzi, Maria Chiara,Monti, Daniela,Parmeggiani, Fabio,Tentori, Francesca
p. 2638 - 2648
(2019/05/16)

Regioselectivity Influences in Platinum-Catalyzed Intramolecular Alkyne O-H and N-H Additions
The steric and electronic drivers of regioselectivity in platinum-catalyzed intramolecular hydroalkoxylation are elucidated. A branch point is found that divides the process between 5-exo and 6-endo selective processes, and enol ethers can be accessed in good yields for both oxygen heterocycles. The main influence arises from an electronic effect, where the alkyne substituent induces a polarization of the alkyne that leads to preferential heteroatom attack at the more electron-deficient carbon. The electronic effects are studied in other contexts, including hydroacyloxylation and hydroamination, and similar trends in directionality are predominant although not uniformly observed.
Costello, Jeff P.,Ferreira, Eric M.
supporting information
p. 9934 - 9939
(2019/12/24)

Leveraging the Halo-Nazarov Cyclization for the Chemodivergent Assembly of Functionalized Haloindenes and Indanones
In this report, we describe a halo-Prins/aryl halo-Nazarov cyclization strategy that employs readily available starting materials, inexpensive reagents, and convenient reaction procedures to generate functionalized haloindenes and indanones. The scope and
Holt, Connor,Alachouzos, Georgios,Frontier, Alison J.
supporting information
p. 5461 - 5469
(2019/03/29)

Modification of the 4-phenylbutyl side chain of potent 3-benzazepine-based GluN2B receptor antagonists
Excitotoxicity driven by overactivation of NMDA receptors represents a major mechanism of acute and chronic neurological and neurodegenerative disorders. Negative allosteric modulators interacting with the ifenprodil binding site of the NMDA receptor are able to interrupt this ongoing neurodamaging process. Starting from the potent 3-benzazepine-1,7-diol 4a novel NMDA receptor antagonists were designed by modification of the N-(4-phenylbutyl) side chain. With respect to developing novel fluorinated PET tracers, regioisomeric fluoroethoxy derivatives 11, 12, 14, and 15 were synthesized. Analogs 19 and 20 with various heteroaryl moieties at the end of the N-side chain were prepared by Sonogashira reaction and nucleophilic substitution. The fluoroethyl triazole 37 was obtained by 1,3-dipolar cycloaddition. In several new ligands, the flexibility of the (hetero)arylbutyl side chain was restricted by incorporation of a triple bond. The affinity towards the ifenprodil binding site was tested in an established competition assay using [3H]ifenprodil as radioligand. Introduction of a fluoroethoxy moiety at the terminal phenyl ring, replacement of the terminal phenyl ring by a heteroaryl ring and incorporation of a triple bond into the butyl spacer led to considerable reduction of GluN2B affinity. The phenol 15 (Ki = 193 nM) bearing a p-fluoroethoxy moiety at the terminal phenyl ring represents the most promising GluN2B ligand of this series of compounds. With exception of 15 showing moderate σ2 affinity (Ki = 79 nM), the interaction of synthesized 3-benzazepines towards the PCP binding site of the NMDA receptor, σ1 and σ2 receptors was rather low (Ki > 100 nM).
Wagner, Marina,Schepmann, Dirk,Ametamey, Simon M.,Wünsch, Bernhard
supporting information
p. 3559 - 3567
(2019/07/03)

MODULATORS OF LIVER RECEPTOR HOMOLOGUE 1 (LRH-1) AND USES
This disclosure relates to modulators of liver receptor homologue 1 (LRH-1) and methods of managing disease and conditions related thereto. In certain embodiments, modulators are derivatives of hexahydropentalene. In certain embodiments, this disclosure r
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(2018/10/19)

Development of Hybrid Phospholipid Mimics as Effective Agonists for Liver Receptor Homologue-1
The orphan nuclear receptor Liver Receptor Homologue-1 (LRH-1) is an emerging drug target for metabolic disorders. The most effective known LRH-1 modulators are phospholipids or synthetic hexahydropentalene compounds. While both classes have micromolar ef
Flynn, Autumn R.,Mays, Suzanne G.,Ortlund, Eric A.,Jui, Nathan T.
supporting information
p. 1051 - 1056
(2018/09/21)

Enantio- A nd regioselective: Ene-reductions using F420H2-dependent enzymes
In the past decade it has become clear that many microbes harbor enzymes that employ an unusual flavin cofactor, the F420 deazaflavin cofactor. Herein we show that F420-dependent reductases (FDRs) can successfully perform enantio-, regio- A nd chemoselective ene-reductions. For the first time, we have demonstrated that F420H2-driven reductases can be used as biocatalysts for the reduction of α,β-unsaturated ketones and aldehydes with good conversions (>99%) and excellent regioselectivities and enantiomeric excesses (>99% ee). Noteworthily, FDRs typically display an opposite enantioselectivity when compared to the well established FMN-dependent Old Yellow Enzymes (OYEs).
Mathew, Sam,Trajkovic, Milos,Kumar, Hemant,Nguyen, Quoc-Thai,Fraaije, Marco W.
supporting information
p. 11208 - 11211
(2018/10/15)

Pd(II)-Catalyzed [4 + 2] Heterocyclization Sequence for Polyheterocycle Generation
A new Pd(II)-catalyzed cascade sequence for the formation of polyheterocycles, from simple starting materials, is reported. The sequence is applicable to both indole and pyrrole substrates, and a range of substituents are tolerated. The reaction is thought to proceed by a Pd(II)-catalyzed C-H activated Heck reaction followed by a second Pd(II)-catalyzed aza-Wacker reaction with two Cu(II)-mediated Pd(0) turnovers per sequence. The sequence can be considered a formal [4 + 2] heterocyclization.
Glaisyer, Elizabeth L.,Watt, Michael S.,Booker-Milburn, Kevin I.
supporting information
p. 5877 - 5880
(2018/09/25)

Stereospecific Alkene Aziridination Using a Bifunctional Amino-Reagent: An Aza-Prilezhaev Reaction
In situ deprotection (TFA) of O-Ts activated N-Boc hydroxylamines triggers intramolecular aziridination of N-tethered alkenes to provide complex N-heterocyclic ring systems. Synthetic and computational studies corroborate a diastereospecific aza-Prilezhaev-type mechanism. The feasibility of related intermolecular alkene aziridinations is also demonstrated.
Farndon, Joshua J.,Young, Tom A.,Bower, John F.
supporting information
p. 17846 - 17850
(2019/01/04)

Regioselective Epoxidations by Cytochrome P450 3A4 Using a Theobromine Chemical Auxiliary to Predictably Produce N-Protected β- or γ-Amino Epoxides
N-Protected β- and γ-amino epoxides are useful chiral synthons. We report here that the enzyme cytochrome P450 3A4 can catalyze the formation of such compounds in a regio- and stereoselective manner, even in the presence of multiple double bonds or aromatic substituents. To this end, the theobromine chemical auxiliary is used not only to control the selectivity of the enzyme, but also as a masked amine, and to facilitate product recovery. Theobromine predictably directed epoxidation at the double bond of the fourth carbon from the theobromine group. Unlike with most catalysts, the selectivity did not depend on electronic or steric factors but rather on the position of the olefin relative to the theobromine group. (Figure presented.).
Polic, Vanja,Cheong, Kin Jack,Hammerer, Fabien,Auclair, Karine
supporting information
p. 3983 - 3989
(2017/11/30)

Lewis acid catalyzed cascade annulation of alkynols with α-ketoesters: A facile access to γ-spiroketal-γ-lactones
A novel Lewis acid catalyzed intermolecular cascade annulation of alkynols with α-ketoesters has been developed. This simple and efficient cascade annulation proceeds through a 5-exo-dig cyclization of alkynols followed by annulation with α-ketoester to provide a wide variety of unsaturated γ-spiroketal-γ-lactones (1,6-dioxaspiro[4.4]non-3-en-2-ones) related to many natural products.
Kambale, Digambar A.,Thorat, Sagar S.,Pratapure, Madhukar S.,Gonnade, Rajesh G.,Kontham, Ravindar
supporting information
p. 6641 - 6644
(2017/07/10)

Highly selective construction of medium-sized lactams by palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes
A novel palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes has been developed. This direct and operationally simple protocol provides a rapid and reliable approach to a diverse array of valuable seven-and eight-membered lactams with high chemoselectivity and regioselectivity. The high selectivity might be attributed to rational tuning the electronic nature of the amine moiety and the palladium catalyst which enabled this transformation to proceed in the absence of acidic or any other additives under fairly mild reaction conditions. This method paves the way for the synthesis of medium-sized lactams.
Hu, Yue,Huang, Hanmin
supporting information
p. 5070 - 5073
(2017/11/07)

Niobium-Catalyzed Intramolecular Addition of O-H and N-H Bonds to Alkenes: A Tool for Hydrofunctionalization
A convenient, versatile, and easy to handle intramolecular hydrofunctionalization of alkenes (C-O and C-N bonds formation) is reported using a novel niobium-based catalytic system. This atom economic and eco-friendly methodology provides an additional synthetic tool for the straightforward formation of valuable building blocks enabling molecular complexity. Various pyran, furan, pyrrolidine, piperidine, lactone, and lactam derivatives as well as spirocyclic compounds are produced in high yields and selectivities.
Ferrand, Laura,Tang, Yue,Aubert, Corinne,Fensterbank, Louis,Mouriès-Mansuy, Virginie,Petit, Marc,Amatore, Muriel
supporting information
p. 2062 - 2065
(2017/04/28)

Palladium-Catalyzed Aerobic Oxidative Cyclization of Aliphatic Alkenyl Amides for the Construction of Pyrrolizidine and Indolizidine Derivatives
An efficient palladium-catalyzed aerobic oxidative cyclization has been developed to synthesize a variety of pyrrolizidine and indolizidine derivatives from simple aliphatic alkenyl amides in moderate to good yields. The reaction features the capability of accessing various N-heterocycles and the use of molecular oxygen (1 atm) as the green oxidant.
Lo, Kai-Yip,Ye, Liu,Yang, Dan
supporting information
p. 1570 - 1575
(2017/08/11)

Palladium NNC Pincer Complex as an Efficient Catalyst for the Cycloisomerization of Alkynoic Acids
A two-step (nucleophilic substitution/palladation by oxidative addition) sequence provides a high-yielding access to a non-symmetrical palladium NNC pincer complex. A number of terminal and internal alkynoic acids with different substitution patterns at the α- and β-positions are regio- and diastereoselectively cycloisomerized to the corresponding exocyclic enol lactones in the presence of exceedingly low amounts of the latter palladium complex, so that unprecedented turnover numbers and frequencies ranging from 1,000,000 to 700,000 and from 41,667 to 9722 h?1, respectively, are achieved. The optimized protocol, based on the use of a catalytic amount of triethylamine as base, allows an easy real-time monitoring of the reaction by NMR spectroscopy. Several pieces of evidence in favor of the direct participation of the above pincer complex as the catalyst of the reaction have been gathered from kinetic and poisoning experiments. (Figure presented.).
Conde, Nerea,SanMartin, Raul,Herrero, María Teresa,Domínguez, Esther
supporting information
p. 3283 - 3292
(2016/10/21)

Gold-catalyzed three-component spirocyclization: A one-pot approach to functionalized pyrazolidines
An efficient, highly atom economic synthesis of hitherto unknown spirocyclic pyrazolidines in a one-pot process was developed. The gold-catalyzed three-component coupling of alkynols, hydrazines and aldehydes or ketones likely proceeds via cycloisomerization of the alkynol to an exocyclic enol ether and subsequent [3 + 2]-cycloaddition of an azomethine ylide. A library of 29 derivatives with a wide range of functional groups was synthesized in up to 97% yield. With this new method, every position in the final product can be substituted which renders the method ideal for applications in combinatorial or medicinal chemistry.
Wagner, Bernd,Hiller, Wolf,Ohno, Hiroaki,Krause, Norbert
supporting information
p. 1579 - 1583
(2016/02/10)

Radical Isomerization and Cycloisomerization Initiated by H? Transfer
Under H2 pressure, CoII(dmgBF2)2L2 (L = H2O, THF) generates a low concentration of an H? donor. Transfer of the H? onto an olefin gives a radical that can either (1) transfer an H? back to the metal, generating an isomerized olefin, or (2) add intramolecularly to a double bond, generating a cyclized radical. Transfer of an H? back to the metal from the cyclized radical results in a cycloisomerization. Both outcomes are favored by the low concentration of the cobalt H? donor, whereas hydrogenation and cyclohydrogenation are more likely with other catalysts (when the concentration of the H? donor is high).
Li, Gang,Kuo, Jonathan L.,Han, Arthur,Abuyuan, Janine M.,Young, Lily C.,Norton, Jack R.,Palmer, Joshua H.
supporting information
p. 7698 - 7704
(2016/07/06)

Cyclization of alk-4-ynals with o-diaminoarenes as a selective one-pot synthesis of arylmethylidene-substituted 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles and 7,8-dihydro-6H-pyrrolo[1’,2’:1,2]imidazo[4,5-b]pyridines
A one-pot synthesis of arylmethylidene-substituted 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles based on the reaction of alk-4-ynals with 1,2-diaminobenzenes in DMSO at sequential catalysis with NH4Br and bases was suggested. The use in these pr
Gvozdev,Shavrin,Baskir,Egorov,Nefedov
p. 1829 - 1838
(2017/03/22)

Cu-catalyzed intramolecular aryl-etherification reactions of alkoxyl alkynes with diaryliodonium salts via cleavage of a stable C-O bond
A novel Cu-catalyzed intramolecular aryl-etherification reaction of alkoxyl alkynes with diaryliodonium salts is realized. The reactions proceed smoothly to produce valuable oxo-heterocycles with readily available linear starting materials via cleavage of a stable C-O bond. This journal is
Chen, Jing,Chen, Chao,Chen, Junjie,Wang, Guohua,Qu, Hongmei
supporting information
p. 1356 - 1359
(2015/02/05)

Regioselective iodoazidation of alkynes: Synthesis of α,α-diazidoketones
Aryl alkyl alkynes reacted with N-iodosuccinimide (NIS) and trimethylsilyl azide (TMSN3), leading to α,α-diazidoketones via the regioselective addition of IN3 to alkynes. Huisgen cyclization of α,α-diazidoketones generated bis-triazo
Okamoto, Noriko,Sueda, Takuya,Minami, Hideki,Miwa, Yoshihisa,Yanada, Reiko
supporting information
p. 1336 - 1339
(2015/03/14)

Chemoselective amination of propargylic C(sp3)-H bonds by cobalt(II)-based metalloradical catalysis
Highly chemoselective intramolecular amination of propargylic C(sp 3)-H bonds has been demonstrated for N-bishomopropargylic sulfamoyl azides through cobalt(II)-based metalloradical catalysis. Supported by D 2h-symmetric amidoporphyrin ligand 3,5-DitBu-IbuPhyrin, the cobalt(II)-catalyzed C-H amination proceeds effectively under neutral and nonoxidative conditions without the need of any additives, and generates N 2 as the only byproduct. The metalloradical amination is suitable for both secondary and tertiary propargylic C-H substrates with an unusually high degree of functional-group tolerance, thus providing a direct method for high-yielding synthesis of functionalized propargylamine derivatives. Make a ring of it: Highly chemoselective intramolecular amination of propargylic C(sp3)-H bonds has been achieved with a high degree of functional-group tolerance through the title reaction. The [Co(P1)]-catalyzed C-H amination proceeds under neutral and nonoxidative conditions without the need of any additives, thus providing a direct method for efficient synthesis of functionalized propargylamine derivatives with N2 as the only by-product.
Lu, Hongjian,Li, Chaoqun,Jiang, Huiling,Lizardi, Christopher L.,Zhang, X. Peter
supporting information
p. 7028 - 7032
(2014/07/08)

Diastereoselective synthesis of highly substituted polycyclic scaffolds via a one-pot four-step tandem catalytic process
A rapid and diastereoselective synthesis of highly substituted aminobicyclo[4.3.0]nonanes and bicyclo[4.4.0]decanes from alkyne derived allylic alcohols has been developed using a one-pot multi-bond forming tandem catalytic process. Overman rearrangement
Grafton, Mark W.,Johnson, Stuart A.,Farrugia, Louis J.,Sutherland, Andrew
p. 7133 - 7141
(2017/09/11)

Cycloisomerization of acetylenic acids to γ-alkylidene lactones using a palladium(II) catalyst supported on amino-functionalized siliceous mesocellular foam
Cycloisomerization of various γ-acetylenic acids to their corresponding γ-alkylidene lactones by the use of a heterogeneous Pd(II) catalyst supported on amino-functionalized siliceous mesocellular foam is described. Substrates containing terminal as well
Nagendiran, Anuja,Verho, Oscar,Haller, Clemence,Johnston, Eric V.,Baeckvall, Jan-E.
p. 1399 - 1405
(2014/03/21)

SmI2-H2O-mediated 5-exo/6-exo lactone radical cyclisation cascades
The SmI2-H2O reagent system mediates challenging 5-exo/6-exo lactone radical cascade cyclisations that deliver carbo[5.4.0]bicyclic motifs in a diastereoselective, one-pot process that establish two new carbocyclic rings and four ste
Yalavac, Irem,Lyons, Sarah E.,Webb, Michael R.,Procter, David J.
supporting information
p. 12863 - 12866
(2015/02/05)

Ethylene transposition: Ruthenium hydride catalyzed intramolecular trans -silylvinylation of internal alkynes
A highly selective intramolecular trans-silylvinylation of internal alkynes catalyzed by RuHCl(CO)(SIMes)(PPh3) has been accomplished. The use of methyl vinyl ketone as an additive increased the efficiency of this transformation. This process w
Liu, Shasha,Zhao, Jinbo,Kaminsky, Lauren,Wilson, Robert J.,Marino, Nadia,Clark, Daniel A.
supporting information
p. 4456 - 4459
(2015/01/16)

Rh(III)-catalyzed intramolecular redox-neutral or oxidative cyclization of alkynes: Short, efficient synthesis of 3,4-fused indole skeletons
A Rh(III)-catalyzed intramolecular redox-neutral or oxidative annulation of a tethered alkyne has been developed to efficiently construct 3,4-fused indoles via a C-H activation pathway. The advantages of this process are (1) ready availability of annulation precursors; (2) broad substrate scope; (3) complete regioselectivity; (4) simple and mild reaction conditions; and (5) no need for an external oxidant or to employ molecular oxygen as the stoichiometric terminal oxidant.
Zhou, Bing,Yang, Yaxi,Tang, Huanyu,Du, Juanjuan,Feng, Huijin,Li, Yuanchao
supporting information
p. 3900 - 3903
(2014/08/18)

A new synthesis of bicyclic N,O- and N,S-enaminals by the anionic cyclization of alk-4-ynals with amino alcohols and amino thiols
A reaction of alk-4-ynals with aliphatic amino alcohols or 2-aminoethanethiol in the system DMSO - KOH gives bicyclic N,O- and N,S-enaminals: 6-methylidenehexahydro-2H-pyrrolo[2,1-b][1,3]oxazines, 5-methylidenehexahydropyrrolo[2,1-b]oxazoles, or 5-methyl-
Gvozdev,Shavrin,Nefedov
p. 409 - 415
(2015/02/02)

Synthesis of enantioenriched aza-proline derivatives through gold(I)-catalyzed cyclization of chiral α-hydrazino esters
A selective gold(I)-catalyzed synthesis of chiral aza-proline derivatives has been developed by ring closure of enantioenriched α-hydrazino esters bearing an alkyne group. These are easily prepared through a synthetic strategy involving two key steps: org
Bouvet, Sebastien,Moreau, Xavier,Coeffard, Vincent,Greck, Christine
p. 427 - 437
(2013/04/10)

Discovery, synthetic methodology, and biological evaluation for antiphotoaging activity of bicyclic[1,2,3]triazoles: In vitro and in vivo studies
Novel bicyclic[1,2,3]triazoles (4, 7, 11, 15) have been synthesized using a one-pot metal free strategy with high structural diversity as photoprotective agents, and their effect on UVA-induced senescence in human dermal fibroblast cells (FB) and the asso
Hsieh, Hsin-Yu,Lee, Wen-Chun,Senadi, Gopal Chandru,Hu, Wan-Ping,Liang, Jium-Jia,Tsai, Tong-Rong,Chou, Yu-Wei,Kuo, Kung-Kai,Chen, Chung-Yu,Wang, Jeh-Jeng
supporting information
p. 5422 - 5435
(2013/07/26)

Synthesis of 6-(arylmethylidene)octahydropyrrolo[1,2-a]pyrimidines and 5-(arylmethylidene)hexahydropyrrolo[1,2-a]imidazoles by the interaction of alk-4-ynals with a,?-diaminoalkanes in DMSO in the presence of KOH
Cyclization of alk-4-ynals with a,?-diaminoalkanes in DMSO under the action of KOH affords bicyclic N,N-enaminals - 6-(aryl- methylidene)octahydro[1,2-a] pyrimidines and 5-(arylmethylidene)hexahydro[1,2-a]imidazoles.
Shavrin, Konstantin N.,Gvozdev, Valentin D.,Nefedov, Oleg M.
p. 140 - 141
(2013/07/26)

Synthesis of bicyclic N,N-enaminals by cyclization of alk-4-ynals with aliphatic diamines in DMSO upon treatment with KOH
A cyclization of alk-4-ynals with aliphatic diamines in DMSO upon treatment with KOH was found to lead to bicyclic N,N-enaminals. The studies of this reaction showed that 1,3-diaminopropane and N-methyl-1,3-diaminopropane gave (E)-6-(arylmethylidene)octahydropyrrolo[1,2-a]pyrimidines in 45 - 78% yields, whereas 1,2-diaminoethane gave 5-(arylmethylidene)hexahydropyrrolo[1,2-a] imidazoles as mixtures of E- and Z-isomers in up to 75% total yield. The mechanism of these new cascade cyclization reactions includes formation of the equilibrium mixtures of imines and cyclic aminals with subsequent intramolecular hydroamination of the triple bond having considerable ionic character.
Gvozdev,Shavrin,Nefedov
p. 2430 - 2437
(2014/11/08)

Multidirectional cobalt-catalyzed diels-alder/1,4-hydrovinylation sequences
The combination of two powerful cobalt-catalyzed carbon-carbon bond forming transformations, namely, the Diels-Alder and the 1,4-hydrovinylation reaction, in a tandem or a sequential one-pot procedure, opened up a concise and efficient route to polysubstituted aromatic systems and cyclohex-3-enone derivatives. Furthermore, ozonolysis of the latter products led to polycarbonyl compounds with tailored carbonyl group distances which could be characterized via their respective BF2-borinane complexes. The cobalt catalysts tolerated several functional groups, and a flexible approach to polyfunctionalized compounds in concise fashion was described.
Erver, Florian,Kuttner, Julian R.,Hilt, Gerhard
p. 8375 - 8385
(2012/11/07)

One-pot catalytic enantioselective synthesis of tetrahydropyridines via a nitro-mannich/hydroamination cascade
The highly enantioselective preparation of synthetically useful tetrahydropyridine derivatives employing a one-pot nitro-Mannich/hydroamination cascade is reported. This approach utilizes an asymmetric organocatalytic nitro-Mannich reaction followed by a gold-catalyzed alkyne hydroamination/ isomerization sequence that yields the desired tetrahydropyridines in good yields and high diastereo- and enantioselectivities.
Barber, David M.,Sanganee, Hitesh J.,Dixon, Darren J.
supporting information
p. 5290 - 5293
(2013/01/15)

Copper-catalyzed highly selective semihydrogenation of non-polar carbon-carbon multiple bonds using a silane and an alcohol
A copper catalyst bearing a suitable Xantphos derivative or NHC ligand was found to be highly efficient for the selective semihydrogenation of non-polar unsaturated compounds using a mixture of a silane and an alcohol as reducing agent. The catalytic system was useful for the selective semihydrogenation of internal alkynes to (Z)-alkenes with suppression of overreduction to the corresponding alkanes. Furthermore, semihydrogenations of terminal alkyne, 1,2-diene, 1,3-diene, 1,3-enyne and 1,3-diyne systems were also achieved selectively. Copyright
Semba, Kazuhiko,Fujihara, Tetsuaki,Xu, Tinghua,Terao, Jun,Tsuji, Yasushi
supporting information; experimental part
p. 1542 - 1550
(2012/08/08)

Intramolecular cyclization and subsequent rearrangements of alkyne-tethered N-heterocyclic carbenes
Alkyne-tethered imidazole and 1,2,4-triazole-based N-heterocyclic carbene precursors have been prepared and studies of the intramolecular reactions of carbenes are performed. Products consistent with intramolecular cyclizations and subsequent rearrangemen
Legault, Marc C.B.,McKay, Craig S.,Moran, Joseph,Lafreniere, Matthew A.,Pezacki, John Paul
supporting information
p. 5663 - 5666
(2012/11/07)

Synthesis of propargylic and allenic carbamates via the C-H amination of alkynes
Propargylic amines are important intermediates for the synthesis of nitrogen-containing heterocycles. The insertion of a nitrene into a propargylic C-H bond has not been explored, despite the attention directed toward the Rh-catalyzed amination of other t
Grigg, R. David,Rigoli, Jared W.,Pearce, Simon D.,Schomaker, Jennifer M.
supporting information; experimental part
p. 280 - 283
(2012/02/16)

Nickel-catalyzed allylic substitution of simple alkenes
This report describes a nickel-catalyzed allylic substitution process of simple alkenes whereby an important structural motif, a 1,4-diene, was prepared. The key to success is the use of an appropriate nickel-phosphine complex and a stoichiometric amount of silyl triflate. Reactions of 1-alkyl-substituted alkenes consistently provided 1,1-disubstituted alkenes with high selectivity. Insight into the reaction mechanism as well as miscellaneous application of the developed catalytic process is also documented.
Matsubara, Ryosuke,Jamison, Timothy F.
supporting information; scheme or table
p. 1860 - 1875
(2012/02/02)

Intramolecular hydroalkoxylation in Bronsted acidic ionic liquids and its application to the synthesis of (±)-centrolobine
The SO3H-tethered imidazolium and triazolium salts, nonvolatile and recyclable Bronsted acidic ionic liquids, efficiently mediate intramolecular hydroalkoxylations of alkenyl alcohols. They have been successfully employed in the synthesis of (±)-centrolobine.
Jeong, Yunkyung,Kim, Do-Young,Choi, Yunsil,Ryu, Jae-Sang
supporting information; experimental part
p. 374 - 378
(2011/02/28)