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Copper-catalyzed three-component: N -alkylation of quinazolinones and azoles
A Cu-catalyzed three-component N-alkylation coupling reaction of N-heteroarenes with methyl ketones and DMPA as a carbon source has been developed. Using methyl ketones as alkylation reagents and DMPA (N,N′-dimethylpropionamide) as a carbon source, the re
Deng, Guo-Jun,Huang, Huawen,Ji, Xiaochen,Wang, Chunlian
supporting information
p. 1200 - 1204
(2022/02/21)

Copper-catalyzed multiple oxidation and cycloaddition of aryl-alkyl ketones (alcohols) for the synthesis of 4-acyl- and 4-diketo-1,2,3-triazoles
A Cu/TEMPO-catalyzed tandem multiple oxidative dehydrogenation and cycloaddition has been developed, which affords 4-acyl-1,2,3-triazoles and 4-diketo-1,2,3-triazoles from readily-available aryl-alkyl ketones (or alcohols) and different organic azides. Moreover, the reaction used environmentally friendly dimethyl carbonate (DMC) as the solvent and air as the oxidant, and H2O was the only by-product, so it provides a green and practical synthetic method for 1,2,3-triazoles.
Chen, Yunfeng,Huang, Liangfeng,Zheng, Lei,Zhou, Zhongzhen
p. 3342 - 3345
(2022/03/31)

Nickel-Catalyzed C(sp3)-H Functionalization of Benzyl Nitriles: Direct Michael Addition to Terminal Vinyl Ketones
An efficient nickel(0)-catalyzed addition of benzyl nitriles to terminal vinyl ketones via C(sp3)-H functionalization has been developed. The reaction provides a novel and efficient protocol for the synthesis of α-functionalized benzyl nitriles with a wide range of structural diversity under mild reaction conditions while obviating the use of a strong base. The work might be potentially useful toward the development of an enantioselective variant using chiral nitrogen ligands.
Zhang, Ninghui,Zhang, Chunli,Hu, Xiaoping,Xie, Xin,Liu, Yuanhong
supporting information
p. 6004 - 6009
(2021/07/31)

Stereoselective Synthesis of Oxacycles via Ruthenium-Catalyzed Atom-Economic Coupling of Propargyl Alcohols and Michael Acceptors
Synthesis of β-hydroxyenones and its application toward development of tetrahydro-4H-pyran-4-one in an atom-economic fashion is limited. This manuscript describes a ruthenium-catalyzed atom-economic coupling of pent-2-yne-1,5-diols and Michael acceptors as an efficient route for the synthesis of β-hydroxyenones with excellent yields and high regioselectivity. The β-hydroxyenones further undergo a 6-endo trig cyclization under acid-catalyzed conditions to deliver the tetrahydro-4H-pyran-4-ones with high diastereoselectivity. An intramolecular aldol condensation under mild basic conditions and palladium-catalyzed oxidative aromatization was developed for the synthesis of hexahydro-6H-isochromen-6-ones and isochromanols, respectively, from highly substituted tetrahydro-4H-pyran-4-ones with excellent yield and diastereoselectivity. Overall, this work demonstrates the synthetic potential toward the synthesis of oxacycles like tetrahydro-4H-pyran-4-ones, hexahydro-6H-isochromen-6-ones, and isochromanols via an atom-economic catalysis.
Bera, Nabakumar,Samanta, Shantanu,Sarkar, Debayan
p. 16369 - 16395
(2021/11/18)

Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol
Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C-C bond and sets a 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension to trisubstituted olefins sets three contiguous stereocenters.
Davis, Colton R.,Luvaga, Irungu K.,Ready, Joseph M.
supporting information
p. 4921 - 4927
(2021/05/04)

Organo-catalyzed Michael addition of 2-fluoro-2-arylacetonitriles
An efficient synthesis of a variety of 2-arylacetonitriles containing a fluorinated stereogenic center through organo-catalyzed Michael addition reaction of 2-fluoro-2-arylacetonitriles has been developed. This protocol uses a cheap organocatalyst (DBU) and has a broad substrate scope: α, β-unsaturated ketones, esters, nitriles and sulfones were all successfully reacted. Importantly, water proved to be a good solvent for this reaction.
Chen, De-Yin,Song, Shuai,Chen, Ling-Yan,Ren, Xinfeng,Li, Ya
supporting information

(2021/03/01)

Mild Darzens Annulations for the Assembly of Trifluoromethylthiolated (SCF3) Aziridine and Cyclopropane Structures
We report mild new annulation approaches to trisubstituted trifluoromethylthiolated (SCF3) aziridines and cyclopropanes via Darzens inspired protocols. The products of these anionic annulations, rarely studied previously, possess attractive features rendering them valuable building blocks for synthesis platforms. In this study, trisubstituted acetophenone nucleophiles bearing SCF3 and bromine substituents in their α position were shown to undergo [2 + 1] annulations with vinyl ketones and tosyl-protected imines under mild reaction conditions.
Delost, Michael D.,Njardarson, Jon T.
supporting information
p. 6121 - 6125
(2021/08/16)

Diastereoselective Photoredox-Catalyzed [3 + 2] Cycloadditions of N-Sulfonyl Cyclopropylamines with Electron-Deficient Olefins
A highly diastereoselective, visible-light-induced [3 + 2] cycloaddition between N-sulfonyl cyclopropylamines and electron-deficient olefins is reported. The reactions proceed via the oxidation of a sulfonamide aza-anion by an organic photocatalyst to generate a nitrogen-centered radical. Strain-induced ring opening and intermolecular addition to the olefin generate an intermediate carbon-centered radical that is reduced to an anion prior to 5-exo cyclization. This enables a highly diastereoselective construction of trans-cyclopentanes possessing synthetically useful functional groups.
White, Dawn H.,Noble, Adam,Booker-Milburn, Kevin I.,Aggarwal, Varinder K.
supporting information
p. 3038 - 3042
(2021/05/04)

Isotope Effects and the Mechanism of Photoredox-Promoted [2 + 2] Cycloadditions of Enones
13C kinetic isotope effects (KIEs) for the photoredox-promoted [2 + 2] cycloaddition of enones were determined in homocoupling and heterocoupling examples. The only significant KIEs were observed at the β carbon, indicating that Cβ-Cβ bond formation is irreversible. However, these KIEs were much lower than computational predictions, suggesting that product selectivity is determined in part by a step prior to Cβ-Cβ bond formation. The results are explained as arising from a competition between C-C bond formation and electron exchange between substrate alkenes. This idea is supported by a relatively small substituent effect on substrate selectivity. The possible rates for electron transfer and bond-forming steps are analyzed, and the competition appears plausible, particularly if the mechanism involves a complex between reduced and neutral enone molecules.
Kuan, Kai-Yuan,Singleton, Daniel A.
p. 6305 - 6313
(2021/05/29)

Design and synthesis of Mannich base-type derivatives containing imidazole and benzimidazole as lead compounds for drug discovery in Chagas Disease
The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease, the most important parasitic infection in Latin America. The only treatments currently available are nitro-derivative drugs that are characterised by high toxicity and limited efficacy. Therefore, there is an urgent need for more effective, less toxic therapeutic agents. We have previously identified the potential for Mannich base derivatives as novel inhibitors of this parasite. To further explore this family of compounds, we synthesised a panel of 69 new analogues, based on multi-parametric structure-activity relationships, which allowed optimization of both anti-parasitic activity, physicochemical parameters and ADME properties. Additionally, we optimized our in vitro screening approaches against all three developmental forms of the parasite, allowing us to discard the least effective and trypanostatic derivatives at an early stage. We ultimately identified derivative 3c, which demonstrated excellent trypanocidal properties, and a synergistic mode of action against trypomastigotes in combination with the reference drug benznidazole. Both its druggability and low-cost production make this derivative a promising candidate for the preclinical, in vivo assays of the Chagas disease drug-discovery pipeline.
Atherton, Richard L.,Kelly, John M.,Olmo, Francisco,Sanz-Serrano, Julen,Alcolea, Verónica,Beltran-Hortelano, Iván,Pérez-Silanes, Silvia,Rubio-Hernández, Mercedes
(2021/07/14)

Facile Synthesis of Polysubstituted 2-Pyrones via TfOH-Mediated Ring Expansion of 2-Acylcyclopropane-1-carboxylates
A facile route to polysubstituted 2-pyrones from readily available 2-acylcyclopropane-1-aryl-1-carboxylates mediated by TfOH is reported. The strongly donating 1-aryl group is important for directing the C-C bond cleavage of the donor-acceptor cyclopropane ring, which then leads to the formation of the 2-pyrone ring through lactonization.
Shao, Jiru,An, Caiyun,Wang, Sunewang R.
p. 4030 - 4041
(2021/07/19)

Effective [3+1+1+1] Cycloaddition to Six-Membered Carbocycle Based on DMSO as Dual Carbon Synthon
A [3+1+1+1] cycloaddition was developed among 2-arylpropene, ketone and DMSO in the presence of K2S2O8. 2-arylpropene provides three carbons, ketone offers one carbon, and DMSO as dual carbon donor contributes two carbons to the six-membered carbocycle. It gave the cyclohexene motif and spirocyclohexene skeleton. Four C?C bonds formed in this process. Both propylene and ketone could be well tolerated and give the corresponding cyclohexene or spirocyclohexene motif in useful yields. Based on the controlled experiments, a possible mechanism was proposed. (Figure presented.).
Li, Hui,Su, Miaodong,Nie, Zhiwen,Yang, Tonglin,Luo, Weiping,Liu, Qiang,Guo, Cancheng
p. 3127 - 3137
(2021/05/17)

Electrochemically driven desaturation of carbonyl compounds
Electrochemical techniques have long been heralded for their innate sustainability as efficient methods to achieve redox reactions. Carbonyl desaturation, as a fundamental organic oxidation, is an oft-employed transformation to unlock adjacent reactivity through the formal removal of two hydrogen atoms. To date, the most reliable methods to achieve this seemingly trivial reaction rely on transition metals (Pd or Cu) or stoichiometric reagents based on I, Br, Se or S. Here we report an operationally simple pathway to access such structures from enol silanes and phosphates using electrons as the primary reagent. This electrochemically driven desaturation exhibits a broad scope across an array of carbonyl derivatives, is easily scalable (1–100 g) and can be predictably implemented into synthetic pathways using experimentally or computationally derived NMR shifts. Systematic comparisons to state-of-the-art techniques reveal that this method can uniquely desaturate a wide array of carbonyl groups. Mechanistic interrogation suggests a radical-based reaction pathway. [Figure not available: see fulltext.]
Gnaim, Samer,Takahira, Yusuke,Wilke, Henrik R.,Yao, Zhen,Li, Jinjun,Delbrayelle, Dominique,Echeverria, Pierre-Georges,Vantourout, Julien C.,Baran, Phil S.
p. 367 - 372
(2021/03/31)

Cobalt(II)-Catalyzed C?H/N?H Functionalization and Annulation of N-(quinolin-8-yl)benzamide with Cyclopropanols
A new method for Co-catalyzed C?H/N?H functionalization and [4+1] annulation of N-(quinolin-8-yl)benzamide with cyclopropanols was developed. This protocol tolerates a variety of functional groups, thereby providing an efficient method for the fabrication of isoindolin-1-ones. Moreover, the utility of this strategy was showcased by the late-stage modification of lithocholic acid derivatives and ibuprofen derivatives.
Chen, Jinkang,Yin, Chuanliu,Zhou, Jian,Yu, Chuanming
supporting information
p. 915 - 923
(2021/02/06)

Nickel-Catalyzed Ring-Opening Allylation of Cyclopropanols via Homoenolate
We report herein a nickel-catalyzed ring-opening allylation of cyclopropanols with allylic carbonates that occurs under mild and neutral conditions. The reaction displays linear selectivity for both linear and branched acyclic allylic carbonates and is also applicable to cyclic allylic carbonates, affording a variety of δ,?-unsaturated ketones in moderate to good yields. Mechanistic experiments are in accord with a catalytic cycle involving decarboxylative oxidative addition of allylic carbonate to Ni(0), alkoxide exchange with cyclopropanol, cyclopropoxide-to-homoenolate conversion on Ni(II), and C-C reductive elimination.
Sekiguchi, Yoshiya,Lee, Yan Ying,Yoshikai, Naohiko
supporting information
p. 5993 - 5997
(2021/08/16)

Enantioselective Copper-Catalyzed Electrophilic Sulfenylation of Cyclic Imino Esters
Herein we report an enantioselective sulfenylation of cyclic imino esters with the efficient and versatile sulfenylation reagent S-alkyl 4-methylbenzenesulfonothioates. By utilizing the Cu/tBu-Phosferrox catalytic system, we can assemble diverse S-alkyl groups into the cyclic imino esters under mild conditions in good yields and with excellent enantioselectivities. Remarkably, this method demonstrates a high tolerance of diverse functional groups and proves to be applicable in the late-stage functionalization of pharmaceuticals.
Chen, Zhiwei,Lin, Huaxin,Han, Jian,Fang, Dongmei,Wang, Min,Liao, Jian
supporting information
p. 9146 - 9150
(2021/11/30)

Iron-Catalyzed ?±,?-Dehydrogenation of Carbonyl Compounds
An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.
Zhang, Xiao-Wei,Jiang, Guo-Qing,Lei, Shu-Hui,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
supporting information
p. 1611 - 1615
(2021/03/03)

Generation of α-Boryl Radicals and Their Conjugate Addition to Enones: Transition-Metal-Free Alkylation of gem-Diborylalkanes
A transition-metal-free method for the alkylation of gem-diborylalkanes with α,β-unsaturated ketones has been developed. It is demonstrated that the α-boryl radicals can be generated efficiently from gem-diborylalkanes with the aid of catechol and oxidants. The α-boryl radicals formed through such process can be engaged in conjugate addition reaction with α,β-unsaturated ketones. This transformation is a straightforward method for the synthesis of γ-borylketones.
Wu, Chaoqiang,Bao, Zhicheng,Dou, Bowen,Wang, Jianbo
supporting information
p. 2294 - 2298
(2021/01/18)

Potassium Base-Catalyzed Michael Additions of Allylic Alcohols to α,β-Unsaturated Amides: Scope and Mechanistic Insights
We report herein the first KHMDS-catalyzed Michael additions of allylic alcohols to α,β-unsaturated amides through allylic isomerization. The reaction proceeds smoothly in the presence of only 5 mol% of KHMDS to afford a variety of 1,5-ketoamides in high yields. Mechanistic investigations, including experimental and computational studies, reveal that the KHMDS-catalyzed in-situ generation of the enolate from the allylic alcohol through a tunneling-assisted 1,2-hydride shift is the key to the success of this transformation. (Figure presented.).
Kurouchi, Hiroaki,Sai, Masahiro
supporting information
p. 3585 - 3591
(2021/06/27)

Ionic liquid [Bmim][AuCl4] encapsulated in ZIF-8 as precursors to synthesize N-decorated Au catalysts for selective aerobic oxidation of alcohols
Here we report a novel approach to synthesize Au NPs immobilized on N-doped carbon materials. In this strategy, an ionic liquid (IL) [Bmim][AuCl4] was selected as the precursor for Au NPs and porous framework of ZIF-8 as the host for the IL. Raman spectroscopy, transmission electron microscopy, N2 physical absorption and Fourier infrared spectra confirmed that the IL was successfully incorporated in the ZIF-8 pores. Followed by a thermal treatment under inert atmosphere, highly dispersed Au NPs were obtained and stabilized by nitrogen species from the carbonization of organic ligand in the metal-organic frameworks (MOFs). The [Bmim][AuCl4]@ZIF-8-6.25percent-T materials exhibited high catalytic activity for the selective aerobic oxidation of alcohols, affording excellent yields (up to >99percent) under atmospheric air and base-free conditions. Catalytic reaction along with catalyst characterization results revealed a strong interaction between Au NPs and N species. TEM, XRD and XPS characterization results further suggested that the N species could not only prevent the Au NPs from aggregation, but also further enhance the reaction activity.
Chen, Fengfeng,Lu, Qingwen,Fan, Ting,Fang, Ruiqi,Li, Yingwei
p. 94 - 102
(2018/12/11)

Palladium-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted: O-carboranes containing α,β-unsaturated carbonyls
With the help of a carboxylic acid directing group, Pd-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted o-carboranes containing α,β-unsaturated carbonyls has been reported. The-COOH, removed during the course of the reaction, is responsible for controlling the regioselectivity. The desired products could be obtained in moderate to good yields.
Li, Jiaoyi,Lu, Jian,Tian, Song,Wang, Qian,Zhang, Chuyi,Zhang, Jianwei,Zhou, Ling
supporting information
p. 4723 - 4727
(2020/07/13)

Asymmetric Synthesis of γ-Secondary Amino Alcohols via a Borrowing-Hydrogen Cascade
The borrowing-hydrogen (or hydrogen autotransfer) process, where the catalyst dehydrogenates a substrate and formally transfers the H atom to an unsaturated intermediate, is an atom-efficient and environmentally benign transformation. Described here is an example of an asymmetric borrowing-hydrogen cascade for the formal anti-Markovnikov hydroamination of allyl alcohols to synthesize optically enriched γ-secondary amino alcohols. By exploiting the Ru-(S)-iPrPyme catalyst with minimal stereogenicity, a cascade process including dehydrogenation, conjugate addition, and asymmetric reduction was developed. The mild conditions, functional group tolerance, and broad substrate scope (54 examples) demonstrate the synthetic practicality of the catalytic system.
Chang, Xiaoyong,Chen, Fumin,He, Dongxu,Jin, Ming Yu,Pan, Yupeng,Xing, Xiangyou,You, Yipeng
supporting information
p. 7278 - 7283
(2020/10/02)

Silyl Radical-Mediated Activation of Sulfamoyl Chlorides Enables Direct Access to Aliphatic Sulfonamides from Alkenes
Single electron reduction is more challenging for sulfamoyl chlorides than sulfonyl chlorides. However, sulfamoyl and sulfonyl chlorides can be easily activated by Cl-atom abstraction by a silyl radical with similar rates. This latter mode of activation was therefore selected to access aliphatic sulfonamides, applying a single-step hydrosulfamoylation using inexpensive olefins, tris(trimethylsilyl)silane, and photocatalyst Eosin Y. This late-stage functionalization protocol generates molecules as complex as sulfonamide-containing cyclobutyl-spirooxindoles for direct use in medicinal chemistry.
Gouverneur, Véronique,Hell, Sandrine M.,Laudadio, Gabriele,Meyer, Claudio F.,Misale, Antonio,No?l, Timothy,Trabanco, Andrés A.,Willis, Michael C.
supporting information
p. 720 - 725
(2020/02/20)

Visible-Light-Driven Nitrogen Radical-Catalyzed [3 + 2] Cyclization of Vinylcyclopropanes and N-Tosyl Vinylaziridines with Alkenes
A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl vinylaziridines with alkenes is developed. Key to the success of this process is the use of the readily tunable hydrazone as a nitrogen radical catalyst. Preliminary mechanism studies suggest that the photogenerated nitrogen radical undergoes reversible radical addition to the vinylcyclopropanes and N-tosyl vinylaziridines to enable their ring-opening C-C and C-N bond cleavage and ensuing cyclization with alkenes.
Chen, Jia-Rong,Wu, Ya-Li,Xiao, Wen-Jing,Xu, Shuang-Hua,Zhao, Quan-Qing,Zhou, Xue-Song
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(2020/03/13)

Copper/Palladium Bimetallic System for the Synthesis of Isobenzofuranones through [4 + 1] Annulation between Propiophenones and Benzoic Acids
A copper/palladium-catalyzed annulation from benzoic acids and propiophenones for the synthesis of isobenzofuranones was reported. The Cu-(2,2,6,6-tetramethylpiperidin-1-yl)oxyl system showed a great ability to activate the C-H bond on the α- and β-carbons of a carbonyl group, and the in situ-generated enone intermediate in this reaction could be further transformed to construct isobenzofuranones with the catalysis of Pd(dba)2 (dba = dibenzylideneacetone). Various isobenzofuranones could be obtained in moderate to good yields, and a great atom economy was highlighted by utilizing this method.
Liang, Xiao,Xiong, Mingteng,Zhu, Heping,Shi, Keqiang,Zhou, Yifeng,Pan, Yuanjiang
supporting information
p. 9568 - 9573
(2020/12/21)

Nature of the Nucleophilic Oxygenation Reagent Is Key to Acid-Free Gold-Catalyzed Conversion of Terminal and Internal Alkynes to 1,2-Dicarbonyls
2,3-Dichloropyridine N-oxide, a novel oxygen transfer reagent, allows the conductance of the gold(I)-catalyzed oxidation of alkynes to 1,2-dicarbonyls in the absence of any acid additives and under mild conditions to furnish the target species, including those derivatized by highly acid-sensitive groups. The developed strategy is effective for a wide range of alkyne substrates such as terminal- and internal alkynes, ynamides, alkynyl ethers/thioethers, and even unsubstituted acetylene (40 examples; yields up to 99%). The oxidation was successfully integrated into the trapping of reactive dicarbonyls by one-pot heterocyclization and into the synthesis of six-membered azaheterocycles. This synthetic acid-free route was also successfully applied for the total synthesis of a natural 1,2-diketone.
Dubovtsev, Alexey Yu.,Shcherbakov, Nikolay V.,Dar'in, Dmitry V.,Kukushkin, Vadim Yu.
p. 745 - 757
(2020/02/04)

Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
supporting information
p. 2086 - 2092
(2020/03/23)

PROCESS FOR THE DIRECT ALPHA-METHYLENATION OF KETONES
The invention relates to a process for preparing an α-methylene ketone comprising the step of reacting a ketone with formaldehyde in the presence of a catalyst which is an organic compound comprising at least one acid function or the corresponding salt, ester or amide thereof and at least one amine function or the corresponding ammonium salt, or a zwitterion thereof.
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(2020/06/10)

Copper-Catalyzed Asymmetric Hydrosilylation of β-Nitroethyl Aryl Ketones
A copper-catalyzed asymmetric hydrosilylation of β-nitroethyl aryl ketones has been disclosed, and the corresponding chiral alcohols could be obtained in high yields (up to 99% yield) and excellent enantioselectivities (up to 96% ee). Moreover, the reaction worked well on a gram scale with 0.3 mol % of ligand loading, indicating that our protocol has potential applications in the synthesis of important pharmaceuticals such as Tranylcypromine and Ticagrelor.
Zeng, Weijun,Tan, Xuefeng,Yu, Yang,Chen, Gen-Qiang,Zhang, Xumu
supporting information
p. 858 - 862
(2020/01/31)

Weak Coordination Enabled Switchable C4-Alkenylation and Alkylation of Indoles with Allyl Alcohols
A weak carbonyl coordination facilitated tunable reactivity between alkenylation and alkylation of indoles at the C4 C-H site is presented using readily accessible allylic alcohols in the presence of Rh catalysis by switching the additives or directing group. Exclusive site selectivity, functional group tolerance, and late-stage modifications are the important practical features.
Banerjee, Sonbidya,De, Pinaki Bhusan,Mishra, Manmath,Pradhan, Sourav,Punniyamurthy, Tharmalingam
supporting information

(2020/03/11)

β-Borylation of conjugated carbonyl compounds with silylborane or bis(pinacolato)diboron catalyzed by Au nanoparticles
Conjugated aldehydes and ketones undergo reaction with Me2PhSiBpin (pin: pinacolato) catalyzed by Au nanoparticles supported on TiO2 forming exclusively the β-borylation products, via the intermediate formation of the labile silaboration adducts. This chemoselectivity pathway is complementary to the so far known analogous reaction catalyzed by other metals, where β-silylation occurs instead. β-Borylation also occurs with pinBBpin under identical reaction conditions in a variety of conjugated carbonyl compounds, including esters and amides which are unreactive in their attempted Au-catalyzed silaboration. This journal is
Fragkiadakis, Michael,Kidonakis, Marios,Stratakis, Manolis
supporting information
p. 8921 - 8927
(2020/11/23)

Copper-Catalyzed Three-Component Formal [3 + 1 + 2] Benzannulation for Carbazole and Indole Synthesis
Three-component formal [3 + 1 + 2] benzannulation reactions of indole-3-carbaldehydes or 1-methyl-pyrrole-2-carbaldehydes with two different molecules of saturated ketones have been successfully developed under Cu-catalyzed and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated conditions. Various unsymmetrically substituted carbazoles and indoles were obtained up to 95% yield. Furthermore, the resulting products exhibit unusual aggregation-induced emission (AIE) properties in the solid state. This method features high atom-economy, cheap catalysts and oxidants, wide substrate scope, and saturated ketones as one-carbon and two-carbon sources, thus providing an efficient approach to polycyclic carbazole and indole compounds.
Guo, Tenglong,Han, Li,Wang, Tingpeng,Lei, Lan,Zhang, Jian,Xu, Dezhu
p. 9117 - 9128
(2020/08/14)

One-Pot Conversion of Allylic Alcohols to α-Methyl Ketones via Iron-Catalyzed Isomerization-Methylation
A one-pot iron-catalyzed conversion of allylic alcohols to α-methyl ketones has been developed. This isomerization-methylation strategy utilized a (cyclopentadienone)iron(0) carbonyl complex as precatalyst and methanol as the C1 source. A diverse range of allylic alcohols undergoes isomerization-methylation to form α-methyl ketones in good isolated yields (up to 84% isolated yield).
Latham, Daniel E.,Polidano, Kurt,Williams, Jonathan M. J.,Morrill, Louis C.
supporting information
p. 7914 - 7918
(2019/10/16)

Catalytic oxidation of alcohols using Fe-bTAML and NaClO: Comparing the reactivity of Fe(V)O and Fe(IV)O intermediates
We demonstrate the selective oxidation of secondary alcohols and activated primary alcohols to their corresponding aldehydes or ketones using Fe-bTAML as the catalyst and sodium hypochlorite (NaClO) as the oxidant. Good to excellent yields of 80%–99% for the carbonyl compounds and turnover numbers up to ～500 was obtained with this catalytic system. The reactions are clean, performed under mild conditions (air, room temperature) and yielded sodium chloride as the only by-product. The yield and turnover number were dependent on the pH of the reaction and this difference was attributed to the different reactive intermediates that was formed at pH 7 and pH 12 (FeV(O) and FeIV(O) respectively). Reactions involving the FeV(O) intermediate oxidize secondary alcohols more efficiently than its FeIV(O) analog. This trend was reversed for the oxidation of activated primary alcohols where reactions involving FeIV(O) afforded much higher TON's. This reactivity trend can be explained from the differences in bond dissociation energy (BDE) of their corresponding one electron reduced species ([FeIV-OH], ～99 kcal/mol; [FeIII-OH], ～83 kcal/mol) as well as their relative stabilities in the solvent during reaction. This catalytic system was found to be unsuitable for nonconjugated primary alcohol due to the formation of the inactive FeIV(OMe) intermediate after one catalytic cycle.
Jana, Sandipan,Thomas, Jithin,Sen Gupta, Sayam
p. 476 - 482
(2018/11/23)

Manganese-Catalyzed Ring-Opening Coupling Reactions of Cyclopropanols with Enones
A manganese-catalyzed ring-opening coupling reaction of cyclopropanols with enones for the facile and efficient preparation of 1,6-diketones is described. A wide array of synthetically important 1,6-diketones bearing manifold functional groups are obtained with up to 93% yield. These reactions feature broad substrate scopes, environmentally benign conditions, inexpensive catalyst, and operational simplicity.
Zhang, Yong-Hui,Zhang, Wen-Wei,Zhang, Ze-Yu,Zhao, Kai,Loh, Teck-Peng
supporting information
p. 5101 - 5105
(2019/07/03)

Aromatic farnesyl compound and application thereof
Aromatic farnesyl compound and application of a pharmaceutical salt thereof as an inhibitor of α-glucosidase, dipeptidyl peptidase-4, aldose reductase, protein tyrosine phosphatase-1B or HMG-CoA reductase, or use thereof in preparing medicine and functional healthcare products having a liver protective function and/or for treating and/or preventing type II diabetes, diabetic retinopathy, diabetic foot disease, and hyperlipidemia.
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(2019/10/29)

Synthesis of Spirobicyclic Pyrazoles by Intramolecular Dipolar Cycloadditions/[1s, 5s] Sigmatropic Rearrangements
The formation of fused pyrazoles via intramolecular 1,3-dipolar cycloadditions of diazo intermediates with pendant alkynes is described. A subsequent thermal [1s, 5s] sigmatropic shift of these pyrazole systems resulted in a ring contraction, forming spirocyclic pyrazoles. The limitations of this rearrangement were explored by changing the substituents on the nonmigrating aromatic ring and by using substrates lacking an aromatic linkage to the propargyl group.
Dimirjian, Christine A.,Casti?eira Reis, Marta,Balmond, Edward I.,Turman, Nolan C.,Rodriguez, Elys P.,Di Maso, Michael J.,Fettinger, James C.,Tantillo, Dean J.,Shaw, Jared T.
supporting information
p. 7209 - 7212
(2019/10/02)

Probing the Effects of Heterocyclic Functionality in [(Benzene)Ru(TsDPENR)Cl] Catalysts for Asymmetric Transfer Hydrogenation
A range of TsDPEN catalysts containing heterocyclic groups on the amine nitrogen atom were prepared and evaluated in the asymmetric transfer hydrogenation of ketones. Bidentate and tridentate ligands demonstrated a mutual exclusivity directly related to their function as catalysts. A broad series of ketones were reduced with these new catalysts, permitting the ready identification of an optimal catalyst for each substrate and revealing the subtle effects that changes to nearby donor groups can exhibit.
Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
supporting information
p. 7223 - 7227
(2019/10/08)

Mn-Enabled Radical-Based Alkyl-Alkyl Cross-Coupling Reaction from 4-Alkyl-1,4-dihydropyridines
Highly efficient alkylation of β-chloro ketones and their derivatives was achieved by means of domino dehydrochlorination/Mn-enabled radical-based alkyl-alkyl cross-coupling reaction. In situ-generated α,β-unsaturated ketones and their analogues were identified as the reaction intermediates. Known bioactive compounds, such as melperone and azaperone, could be easily prepared from β-chloropropiophenone in two steps.
Wang, Jie,Pang, Yu-Bo,Tao, Na,Zeng, Run-Sheng,Zhao, Yingsheng
p. 15315 - 15322
(2019/11/19)

Ruthenium-Catalyzed Redox Isomerizations inside Living Cells
Tailored ruthenium(IV) complexes can catalyze the isomerization of allylic alcohols into saturated carbonyl derivatives under physiologically relevant conditions, and even inside living mammalian cells. The reaction, which involves ruthenium-hydride intermediates, is bioorthogonal and biocompatible, and can be used for the "in cellulo" generation of fluorescent and bioactive probes. Overall, our research reveals a novel metal-based tool for cellular intervention, and comes to further demonstrate the compatibility of organometallic mechanisms with the complex environment of cells.
Vidal, Cristian,Tomás-Gamasa, María,Gutiérrez-González, Alejandro,Mascarenas, José L.
supporting information
p. 5125 - 5129
(2019/03/29)

Efficient AcrH2 Catalyzed β-Trifluoromethylation of Carbonyl Compounds by Atom Transfer Radical Addition Reactions
The use of organic catalysis AcrH2 enables the direct β-trifluoromethylation of carbonyl compounds by atom transfer radical addition reactions with broad substrate scopes under mild conditions. This operationally simple and robust protocol successfully converts a variety of β-chloro carbonyl compounds into the corresponding α-chloro-β-fluoroalkylcarbonyl products. A significant advantage of this method is that it does not require the use of a metal catalyst, thereby avoiding metal residue problems in drug synthesis.
Rao, Zi-Peng,Sun, Yu-Yang,Zhou, Xin-Feng,Xie, Qiang,Zhu, Hui-Xia,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
supporting information
p. 1025 - 1030
(2019/08/30)

A General One-Pot Methodology for the Preparation of Mono- and Bimetallic Nanoparticles Supported on Carbon Nanotubes: Application in the Semi-hydrogenation of Alkynes and Acetylene
A facile and straightforward methodology for the preparation of monometallic (copper and palladium) and bimetallic nanocatalysts (NiCu and PdCu) stabilized by a N-heterocyclic carbene ligand is reported. Both colloidal and supported nanoparticles (NPs) on carbon nanotubes (CNTs) were prepared in a one-pot synthesis with outstanding control on their size, morphology and composition. These catalysts were evaluated in the selective hydrogenation of alkynes and alkynols. PdCu/CNTs revealed an efficient catalytic system providing high selectivity in the hydrogenation of terminal and internal alkynes. Moreover, this catalyst was tested in the semi-hydrogenation of acetylene in industrially relevant acetylene/ethylene-rich model gas feeds and showed excellent stability even after 40 h of reaction.
Lomelí-Rosales, Diego A.,Delgado, Jorge A.,Díaz de los Bernardos, Miriam,Pérez-Rodríguez, Sara,Gual, Aitor,Claver, Carmen,Godard, Cyril
supporting information
p. 8321 - 8331
(2019/06/04)

Photocatalytic C(sp3)?H Activation towards α-methylenation of Ketones using MeOH as 1 C Source Steering Reagent
Unprecedented direct access to terminal enones via α-methylenation of aryl ketones to form C=C bond is achieved under visible-light conditions using methanol as one carbon source substrate and solvent as well. The reaction involves Cu@g-C3N4-catalysed in situ oxidation of methanol into formaldehyde followed by dehydrative cross aldol type reaction. Various aryl ketones react efficiently with MeOH, producing α,β-unsaturated carbonyl compounds only in 4–8 h at room temperature in excellent yield (84–97%). Operational simplicity, wide substrate scope, ambient reaction conditions, visible-light photocatalysis and novel application of MeOH as methylene donor substrate are the salient features making the envisaged protocol mild, efficient and green alternative to the existing methods for synthesis of such fine chemicals. (Figure presented.).
Verma, Fooleswar,Shukla, Prashant,Bhardiya, Smita R.,Singh, Manorama,Rai, Ankita,Rai, Vijai K.
supporting information

(2019/02/05)

Rh-Catalyzed Decarbonylative Addition of Salicylaldehydes with Vinyl Ketones: Synthesis of Taccabulins A–E
A rhodium-catalyzed decarbonylative addition of salicylaldehydes with vinyl ketones was developed to synthesize o-hydroxydihydrochalcones (2-hydroxyphenethyl ketones). These decarbonylative addition reactions afforded various functionalized o-hydroxydihydrochalcones in moderate to good yields with broad functional group tolerance and selectivity. This method was also applied further in the divergent synthesis of dihydrochalcone derived taccabulins A–E.
Rao, Maddali L. N.,Ramakrishna, Boddu S.
p. 7545 - 7554
(2019/12/15)

Iron-Catalyzed Tandem Three-Component Alkylation: Access to α-Methylated Substituted Ketones
The borrowing hydrogen strategy has been applied in the synthesis of α-branched methylated ketones via a tandem three-component reaction catalyzed by a diaminocyclopentadienone iron tricarbonyl complex. Various alkyl and aromatic methyl ketones underwent dialkylation with various primary alcohols and methanol as alkylating agents in mild reaction conditions and good yields. Deuterium labeling experiments suggested that the benzylic alcohol was the hydrogen source in this tandem process.
Bettoni, Léo,Seck, Charlotte,Mbaye, Mbaye DIagne,Gaillard, Sylvain,Renaud, Jean-Luc
supporting information
p. 3057 - 3061
(2019/05/10)

Alkylation of Indoles with α,β-Unsaturated Ketones using Alumina in Hexanes
We evaluated the influence of solvent on the alumina-promoted C3-alkylation of indoles with α,β-unsaturated ketones. We found that lipophilic solvents were generally superior to hydrophilic ones with hexanes offering the 3-alkyl indole products in high yields. Thus, we demonstrate an inexpensive and procedurally simple new process that pairs acidic alumina with hexanes to achieve this important Michael alkylation. The substrate scope includes twenty-four examples with reaction yields ranging from 61 to 96%. (Figure presented.).
Zhang, Xiong,Jones-Mensah, Ebenezer,Deobald, Jackson,Magolan, Jakob
supporting information
p. 5548 - 5551
(2019/11/19)

Direct Assembly of Polysubstituted Furans via C(sp3)?H Bond Functionalization by Using Dimethyl Sulfoxide as a Dual Synthon
An unusual I2-mediated triple C(sp3)?H functionalization reaction between aryl methyl ketones and dimethyl sulfoxide to form polysubstituted furans has been developed. In this transformation, dimethyl sulfoxide functions as a dual synthon via C(sp3)?H functionalization with formation of two C?C bonds, one C?O bond, and one C?S bond in a one-step process. Iodine is crucial as promoter of the reaction, by which a number of ketones could be converted easily into 2,4,5-trisubstituted furans. This provides an extremely simple and expeditious approach to high-value-added, biologically significant O-heterocycles. Based on preliminary experiments, a plausible mechanism is proposed. (Figure presented.).
Liu, Yufeng,Hu, Yuqun,Cao, Zhongzhong,Zhan, Xi,Luo, Weiping,Liu, Qiang,Guo, Cancheng
p. 1084 - 1091
(2019/01/30)

Fe-Catalyzed enaminone synthesis from ketones and amines
We have developed an iron-catalyzed direct olefination for enaminone synthesis, with saturated ketones as a source of olefins. This direct ketone β-functionalization reaction has readily available starting materials and a wide range of substrates and requires mild reaction conditions.
Wu, Wenfeng,Wang, Zhuxian,Shen, Qun,Liu, Qiang,Chen, Huoji
supporting information
p. 6753 - 6756
(2019/07/22)

Co(II)/Cu(II)-cocatalyzed oxidative C-H/N-H functionalization of benzamides with ketones: A facile route to isoindolin-1-ones
A cobalt and copper catalyzed reaction protocol has been developed to achieve the oxidative C-H/N-H annulation of benzamides containing an 8-aminoquinoline moiety as the directing group with ketones. Structurally diverse isoindolin-1-ones were furnished by the reaction of various substituent benzamides with ketones.
Zhou, Xi,Xu, Hongyan,Yang, Qiaodan,Chen, Hua,Wang, Shoufeng,Zhao, Huaiqing
supporting information
p. 8603 - 8606
(2019/07/25)

Mechanistic Investigation of Enantioconvergent Kumada Reactions of Racemic α-Bromoketones Catalyzed by a Nickel/Bis(oxazoline) Complex
In recent years, a wide array of methods for achieving nickel-catalyzed substitution reactions of alkyl electrophiles by organometallic nucleophiles, including enantioconvergent processes, have been described; however, experiment-focused mechanistic studies of such couplings have been comparatively scarce. The most detailed mechanistic investigations to date have examined catalysts that bear tridentate ligands and, with one exception, processes that are not enantioselective; studies of catalysts based on bidentate ligands could be anticipated to be more challenging, due to difficulty in isolating proposed intermediates as a result of instability arising from coordinative unsaturation. In this investigation, we explore the mechanism of enantioconvergent Kumada reactions of racemic α-bromoketones catalyzed by a nickel complex that bears a bidentate chiral bis(oxazoline) ligand. Utilizing an array of mechanistic tools (including isolation and reactivity studies of three of the four proposed nickel-containing intermediates, as well as interrogation via EPR spectroscopy, UV-vis spectroscopy, radical probes, and DFT calculations), we provide support for a pathway in which carbon-carbon bond formation proceeds via a radical-chain process wherein a nickel(I) complex serves as the chain-carrying radical and an organonickel(II) complex is the predominant resting state of the catalyst. Computations indicate that the coupling of this organonickel(II) complex with an organic radical is the stereochemistry-determining step of the reaction.
Yin, Haolin,Fu, Gregory C.
supporting information
p. 15433 - 15440
(2019/10/22)