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Results in Journal Organic Letters: 35,249

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Feng Zhang, Yang Wang, , Yi Pan
Published: 14 September 2021
Abstract:
This work describes an electrochemically promoted nickel-catalyzed deoxygenative thiolation of alcohols and ketones under mild conditions. Excellent substrate tolerance and good chemical yields can be achieved by graphene/nickel foam electrodes in an undivided cell. Further study to gain mechanistic insight into this electrochemical cross-coupling has been carried out.
Fu-Sheng He, Ping Bao, Feiyan Yu, Ling-Hui Zeng, ,
Published: 14 September 2021
Abstract:
By employing CuOAc as the catalyst, we realize a four-component reaction of 1,3-enynes, diselenides, DABCO·(SO2)2, and cycloketone oxime esters, providing facile access to diverse cyanoalkylsulfonylated allenyl selenides in moderate to good yields. This reaction features high functional group tolerance and a broad substrate scope, enabling the regioselective, sequential formation of C–SO2 and C–Se bonds under mild reaction conditions. Moreover, the utility of this methodology is further illustrated through the late-stage functionalization of drug-based molecules.
Dasari Srinivas,
Published: 14 September 2021
Abstract:
Herein, we present m-C–H olefination on derivatives of phenylacetic acids by tethering with a simple nitrile-based template through palladium catalysis. Notably, the versatility of the method is evaluated with a wide range of phenylacetic acid derivatives for obtaining the meta-olefination products in fair to excellent yields with outstanding selectivities under mild conditions. Significantly, the present strategy is successfully exemplified for the synthesis of drugs/natural product analogues (naproxen, ibuprofen, paracetamol, and cholesterol).
Manzoor Ahmad, Sandip Chattopadhayay, Debashis Mondal, ,
Published: 14 September 2021
Abstract:
Photoswitchable acylhydrazone-based synthetic anionophores are reported. Single-crystal X-ray structure and 1H NMR titration studies confirmed the chloride binding in solid and solution states. The ion transport activity of 1a was greatly attenuated through a phototriggered E to Z photoisomerization process, and the photoisomerized deactivated state showed high kinetic stability due to an intramolecular hydrogen bond. Switchable “OFF–ON” transport activity was achieved by the application of light and acid-catalyzed reactivation process.
Xue Li, Fang Bai, Chaogan Liu, Xiaowei Ma, Chengzhi Gu, Bin Dai
Published: 13 September 2021
Abstract:
An efficient electrochemical method for benzylic C(sp3)–H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
Yong Xu, Zhen Wang,
Published: 12 September 2021
Abstract:
The enantioselective [3 + 1]-cycloaddition of two structurally different diazo compounds has been achieved using chiral bisoxazoline copper(I) complexes as a catalyst, providing a novel route for the synthesis of cyclobutenes containing a quaternary stereocenter. Typically, this reaction represents the first example of asymmetric cross-electrophile coupling of two diazo substrates via carbene discrimination.
Avishek Guin, Rahul N. Gaykar, Shiksha Deswal,
Published: 12 September 2021
Abstract:
A transition-metal-free, three-component, and diastereoselective [6 + 3] annulation reaction employing tropone, imino esters, and arynes allowing the synthesis of bridged azabicyclo[4.3.1]decadienes is demonstrated. The key nitrogen ylides for the [6 + 3] annulation were generated by the addition of imino esters to the arynes followed by a proton transfer. The nitrogen ylides undergo a regioselective addition to tropone to furnish the desired products in moderate to good yields with good functional group tolerance under mild conditions.
Akash Bandu Jamdade, Dashrat Vishambar Sutar, Girish Singh Bisht,
Published: 10 September 2021
Abstract:
Herein we describe a new approach for end-to-end cyclization to construct macrocycles through the inter/intramolecular dehydrogenative coupling of alcohols and ketones in the presence of a Ru-MACHO catalyst. This method is highly atom economical and sustainable and can be used for many substrates. Additionally, this method results in the generation of only water as the byproduct. Moreover, in this approach, high dilution of the reactants is crucial for cyclization and high-yield macrocycle synthesis.
Jun Chen, Zhan Shi,
Published: 10 September 2021
Abstract:
A practical synthesis of enantioenriched indane derivatives with quaternary stereocenters was developed via sequential enantioselective reduction and C–H functionalization. Good to excellent enantioselectivity could be achieved by either the CuH-catalyzed asymmetric reduction or the Corey–Bakshi–Shibata (CBS) reduction of indanone derivatives. The subsequent diastereospecific and regioselective rhodium-catalyzed silylation of the methyl C–H bond led to indane derivatives with quaternary centers. This strategy was further applied in syntheses of (nor)illudalane and botryane sesquiterpenoids.
Caifang Han, ,
Published: 10 September 2021
Abstract:
By the use of a chiral frustrated Lewis pair (FLP) consisting of a chiral-diene-derived borane and tBu3P as the catalyst, an asymmetric halocyclization of 2-vinylbenzyl alcohols with NBS or NIS was successfully realized. A variety of optically active 1,3-dihydroisobenofuran derivatives were obtained in high yields with up to 87% ee and could be conveniently converted to other useful chiral compounds.
Juliane Chaud, Clément Morville, , Delphine Garnier, , ,
Published: 10 September 2021
Abstract:
We herein report the design, synthesis, and photophysical characterization of extended and rigid coumarinyl derivatives showing large two-photon sensitivities (δaΦu ≤ 125 GM) at 740 and 800 nm. To efficiently synthesize these complex photoremovable protecting groups (PPGs), we used step-economic domino reactions. Moreover, those new coumarinyl PPGs display unique bathochromic shifts (≤100 nm) of the uncaging subproducts as a result of the formation of a more conjugated fulvene moiety.
Linhong Zuo, Pengchen Ma, Teng Liu, , Robert H. Lavroff, Wei-Peng Chen, ,
Published: 10 September 2021
Abstract:
We report the catalytic generation of a vinyl Pd-oxyallyl that dimerizes regiospecifically to form highly functionalized nonbridged cyclooctanoids. Such compounds are otherwise synthetically challenging, but highly useful in synthesis. This vinyl Pd-oxyallyl species demonstrates both electrophilic and nucleophilic properties. DFT calculations elucidate the mechanism and the origins of the chemoselective cyclooctanoid formation.
Cynthia Messina, ,
Published: 10 September 2021
Abstract:
Herein, we report a modular synthetic route to access tetra-arylated thiophene compounds with four different substituents with programmed chemical control provided by an ester activating/directing group. This method enables the functionalization of individual positions of thiophene sequentially via regioselective halogenations and cross-coupling reactions. The reaction sequence described provides tetra-arylated thiophenes in higher yields than previous routes and employs practical reaction protocols, simple catalytic systems, and short reaction times.
, Fan Wang, Xue-Ya Gou, Ying-Hui Yang, Wan-Yuan Jia, , Xi-Cun Wang, Yuke Li,
Published: 10 September 2021
Abstract:
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 “ortho effect” and then undergo N–S bond cleavage with vinyl palladium, thus achieving a highly selective C–N coupling reaction in the Catallani–Lautens reaction system. On the basis of this discovery, a one-step synthesis of highly functionalized tricyclic indole derivatives was realized.
Juan Hua, Yan-Chun Liu, , , Xiao-Nian Li,
Published: 10 September 2021
Abstract:
Two novel triterpenoid saponins, colqueleganoids A (1) and B (2), with the first methyl-30 incorporated 6/6/6/6-cyclized carbon skeleton (named colquelegane), were isolated from the root of Colquhounia elegans. Their structures including absolute configuration were determined by spectroscopic methods and X-ray crystallographic analyses. Interestingly, both compounds significantly enhanced TNF-α production and 1 also increased the IL-6 production in RAW264.7 macrophages stimulated with lipopolysaccharide (LPS), suggesting their potential application as immunostimulants in immunotherapy and vaccination.
Michał Ociepa, Kyle W. Knouse, David He, Julien C. Vantourout, Dillon T. Flood, Natalia M. Padial, Jason S. Chen, Brittany B. Sanchez, Emily J. Sturgell, Bin Zheng, et al.
Published: 9 September 2021
Abstract:
An operationally simple, scalable, and chemoselective method for the direct phosphorylation of alcohols using a P(V)-approach based on the Ψ-reagent platform is disclosed. The method features a broad substrate scope of utility in both simple and complex settings and provides access to valuable phosphorylated alcohols that would be otherwise difficult to obtain.
Jinlong Zhao, Jiarong Shi,
Published: 9 September 2021
Abstract:
A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
Jiaming Li, Jian Li, Xiaoliang Ji, Runfa He, Yang Liu, Zebin Chen, Yubing Huang, , Yibiao Li
Published: 9 September 2021
Abstract:
Herein we have developed a reversible hydrogen–deuterium exchange reaction of nonactivated olefins. By using EtOCS2K as a mediator, the H/D exchange reaction was realized through repeated addition and elimination reactions, demonstrating reversible H/D exchange between ordinary olefins and deuterated olefins. Using the lowest cost D2O without precious metal catalysts and ligands, a broad spectrum of compatibility of functional groups was achieved.
Thiago dos Santos, Henrique P. Orenha, Valter E. Murie, Ricardo Vessecchi,
Published: 9 September 2021
Abstract:
We have accomplished regioselective deprotometalation of aromatic and heteroaromatic nitriles via (TMP)2Zn·2MgCl2·2LiCl and TMPMgCl·LiCl (TMP = 2,2,6,6-tetramethylpiperidyl) with the exploration of new and scarcely investigated metalation positions. Regioselectivity was rationalized by DFT calculations. The quenching of the generated organozinc and organomagnesium intermediates with various electrophiles gave access to 47 highly functionalized nitriles with yields up to 95%. Additionally, we report a difunctionalization strategy and the use of functionalized nitriles as building blocks to construct relevant heterocycles.
Mrityunjay Gupta, Monika Singha, Dnyaneshwar B. Rasale, Zehao Zhou, Srijana Bhandari, Samantha Beasley, Jasmine Sakr, ,
Published: 8 September 2021
Abstract:
We report a strategy for the orthogonal conjugation of the vinyl nucleosides, 5-vinyluridine (5-VU) and 2-vinyladenosine (2-VA), via selective reactivity with maleimide and tris(2-carboxyethyl)phosphine (TCEP), respectively. The orthogonality was investigated using density functional theory (DFT) and confirmed by reactions with vinyl nucleosides. Further, these chemistries were used to modify RNA for fluorescent cell imaging. These reactions allow for the expanded use of RNA metabolic labeling to study nascent RNA expression within different RNA populations.
Yan Liu, Xian Peng, Rui She, Xin Zhou,
Published: 8 September 2021
Abstract:
The unique structure of oxyallyls represents a significant challenge for their catalytic asymmetric applications. Herein, an unprecedented chiral imidodiphosphoric acid-catalytic enantioselective (3 + 3) cycloaddition between oxyallyl zwitterions generated in situ from α-haloketones and α-diazomethylphosphonates was developed. Pharmaceutically interesting chiral pyridazine-4(1H)-ones were obtained in up to 98% yields with excellent stereoselectivities (up to 99% ee, > 99:1 dr).
Fuyang Yue, Jianyang Dong, ,
Published: 8 September 2021
Abstract:
Herein, we report a protocol for direct visible-light-mediated C–I difluoroallylation reactions of α-trifluoromethyl arylalkenes with alkyl iodides at room temperature with an α-aminoalkyl radical as a mediator. The protocol permits efficient functionalization of various α-trifluoromethyl arylalkenes with cyclic and acyclic primary, secondary, and tertiary alkyl iodides and is scalable to the gram level. This mild protocol uses an inexpensive mediator and is suitable for late-stage functionalization of complex natural products and drugs.
Jieyan Lim, Venkaiah Chintalapudi, Haraldur G. Gudmundsson, Minh Tran, Alice Bernasconi, Araceli Blanco, Lijiang Song, ,
Published: 8 September 2021
Abstract:
The stambomycins are a family of bioactive macrolides isolated from Streptomyces ambofaciens. Aside from two stereocenters installed through cytochrome P450 oxidations, their stereochemistry has been predicted by sequence analysis of the polyketide synthase. We report a synthesis of the C1–C27 fragment of stambomycin D, the spectroscopic data of which correlates well with that of the natural product, further validating predictive sequence analysis as a powerful tool for stereochemical assignment of complex polyketide natural products.
Daiki Doiuchi,
Published: 8 September 2021
Abstract:
We found that the oxygen atom of water is activated to iodosylbenzene derivatives via reversible hydrolysis of PhI(OOCR)2 and can be used to the oxygen source for ruthenium(bpga)-catalyzed site-selective C–H oxygenation. Ru(bpga)/PhI(OOCR)2/H2O system, sterically less bulky methinic and methylenic C–H bonds in various compounds can be converted to desired oxygen functional groups in a site-selective manner. Using this method, oxygen-isotope labeled compounds such as d-[3-17O/18O]-mannose can be prepared in a multigram scale.
Sudarshan Debnath, Mei Lu, Lingli Liang,
Published: 7 September 2021
Abstract:
An efficient tandem nucleophilic aminopalladation and carbene insertion sequence is described for the synthesis of indole fused polycycles. The reaction process provides a variety of substituted indeno[1,2-b]indoles in up to 99% yields.
Yu-Ting Hsiao, Jonathan Beadle, Cameron Pascoe, Ritesh Annadate,
Published: 7 September 2021
Abstract:
Syntheses of stereochemically pure and selectively protected diamino diacids can be achieved by redox decarboxylation of distal N-hydroxyphthalimide esters of protected aspartic, glutamic or α-aminoadipic acids via radical addition to methylideneoxazolidinones. The products are useful for solid-supported syntheses of robust bioactive carbocyclic peptide analogs. Yields of reactive primary radical addition are superior to those of more stabilized radicals, and the reaction fails if the alkylideneoxazolidinone has a methyl substituent on its terminus (i.e., 13a/13b).
Yan Li, Laura Grauso, Silvia Scarpato, Nunzio Antonio Cacciola, Francesca Borrelli, ,
Published: 7 September 2021
Abstract:
Two diarylheptanoid heterodimers, zosterabisphenones A (1) and B (2), were isolated from the seagrass Zostera marina. They feature unprecedented catechol keto tautomers, stable because of steric constraints. Their structure elucidation was based on extensive low-temperature NMR studies and ECD and MS data, with the essential aid of DFT prediction of NMR and ECD spectra. Zosterabisphenone B (2) was selectively cytotoxic against the adenocarcinoma colon cancer cell line HCT116 with IC50 3.6 ± 1.1 μM at 48 h.
Chunxiang Pan, Chunhui Yang, Kangkui Li, Keyang Zhang, Yuanbin Zhu, Shiyuan Wu, Yongyun Zhou,
Published: 7 September 2021
Abstract:
An efficient, catalyst/photocatalyst-free, and cost-effective methodology for the decarboxylative alkylation of α,β-unsaturated carboxylic acids to synthesize β,γ-unsaturated nitriles has been developed. The reaction proceeded in an environmentally benign atmosphere of blue light-emitting diode irradiation with K2CO3 and water at room temperature. The methodology worked for a wide range of substrates (22 examples) with up to 83% yield. The protocol is also compatible for gram-scale synthesis.
Iñaki Urruzuno, Paula Andrade-Sampedro,
Published: 3 September 2021
Abstract:
The selective tagging of amino acids within a peptide framework while using atom-economical C–H counterparts poses an unmet challenge within peptide chemistry. Herein, we report a novel Pd-catalyzed late-stage C–H acylation of a collection of Tyr-containing peptides with alcohols. This water-compatible labeling technique is distinguished by its reliable scalability and features the use of ethanol as a renewable feedstock for the assembly of a variety of peptidomimetics.
Zhuo Wu, Zechen Wu, Xueliang Sun, Weixin Qi, Zhengyang Zhang,
Published: 3 September 2021
Abstract:
Direct C–H/C–H coupling represents an appealing method for the construction of C–C bonds, and the cross-coupling of unactivated C(sp3)–H and C(sp2)–H bonds is challenging and remains to be investigated. We have developed the Pd-catalyzed intramolecular coupling of inert C(sp3)–H and C(sp2)–H bonds. The reaction proceeded by o-methyl oxime-directed aryl C(sp2)–H activation and subsequent alkyl C(sp3)–H cleavage, generating C(sp2),C(sp3)-palladacycles as the key intermediates. Dihydrobenzofurans and indanes were formed as the final products.
Luis M. Mori-Quiroz, Chelsea G. Comadoll, Jonathan E. Super,
Published: 3 September 2021
Abstract:
New methods for C–N bond construction exploiting the N-centered electrophilic character of iminoquinones are reported. Iminoquinones, generated in situ via the condensation of o-vinylanilines with benzoquinones, undergo acid-catalyzed cyclization to afford N-arylindoles in excellent yields. Under similar reaction conditions, homoallylic amines react analogously to afford N-arylpyrroles. Additionally, organometallic nucleophiles are shown to add to the nitrogen atom of N-alkyliminoquinones to provide amine products. Finally, iminoquinones are shown to be competent electrophiles for copper-catalyzed hydroamination.
Tian-Zhen Xie, Lei Luo, Yun-Li Zhao, Hao Li, Mei-Ling Xiang, Xu-Jie Qin, , Yan-Yan Zhu, Zhi Dai, Zhao-Jie Wang, et al.
Published: 3 September 2021
Abstract:
Two distinctive alkaloids with 6/6/6/5/6/6 fused rings, in which a previously unidentified linkage of C-12/23 generates a rigid skeleton, resulting in a new subtype of steroidal alkaloid, were isolated from Veratrum grandiflorum. Compounds 1 and 2 showed potent analgesic effects in vivo, superior to the well-known analgesic, pethidine (Dolantin), likely by inhibiting CaV2.2 voltage-gated calcium channels.
Ruxia Mao, Yanliang Zhao, Xiaohan Zhu, Fen Wang, ,
Published: 3 September 2021
Abstract:
Enantioenriched allenes are important building blocks. While they have been accessed by other coupling methodologies, enantioenriched allenes have been rarely obtained via C–H activation. In this work, kinetic resolution of tertiary propargyl alcohols as an allenylating reagent has been realized via rhodium(III)-catalyzed C–H allenylation of benzamides. The reaction proceeded efficiently under mild conditions, and both the allenylated products and the propargyl alcohols were obtained in high enantioselectivities with an s-factor of up to 139. The resolution results from bias of the two propargylic substituents and is assisted by a chiral zinc carboxylate additive.
Huai-Wei Wang, Jia-Xue Wu, Yu-Han Qiao, Yong-Fei Li, Da-Cheng Li, Jian-Min Dou, Qing-Xia Yao,
Published: 2 September 2021
Abstract:
Herein, we disclose a RhIII-catalyzed heteroarylation of C(sp3)–H and C(sp2)–H bonds in heterocycles with organoboron reagents. This protocol displays high efficiency and excellent functional group tolerance. A range of heterocyclic boronates with strong coordinating atoms, including pyridine, pyrimidine, pyrazole, thiophene, and furan derivatives, can be extensively served as the coupling reagents. The direct heteroarylation method could supply potential application in terms of the synthesis of drug molecules with multiple heterocycles.
Amy L. Mayhugh,
Published: 2 September 2021
Abstract:
A robust method of room temperature direct arylation for benzofuran is reported. This discovery allows for mild arylation by commercially available aryl iodides with complete C-2 regioselectivity and tolerates a range of functional groups, including heat sensitive groups. Mechanistically, a Heck-type oxyarylation product from a direct arylation process is reported as a key piece of evidence for a carbopalladation intermediate.
Yan-E Zhang, ,
Published: 2 September 2021
Abstract:
Despite their unique structures, tantalizing properties, and potential applications in carbon nanoscience and technology, the synthesis and functionalization of zigzag hydrocarbon nanobelts have remained largely unexplored until recently. Reported herein is the selective transformations of belt[4]arene[4]tropilidenes and their application in the construction of novel belts. The oxidation of belt[4]arene[4]tropilidene with benzeneseleninic anhydride under controlled conditions selectively afforded mono- to tetrakis(α-diketone)-functionalized belt intermediates. A subsequent condensation reaction with 1,2-phenylenediacetonitrile and 1,2-phenylenediamine produced a diversity of unprecedented belts with various macrocyclic cavities.
Xiao Jin, Vijay K. Chatare, Po-Cheng Yu, Michael R. Gau, Owen T. O’Sullivan,
Published: 2 September 2021
Abstract:
The domino Michael/Mannich (DMM) annulation reaction between an N-sulfinyl lithiodienamine and an electrophilic alkene is developed for the synthesis of chiral 2-amino cyclohexenes, a key building block in asymmetric synthesis. The DMM reaction proceeds at low temperature while maintaining the stereochemical fidelity. The product functionalized amino cyclohexenes, here obtained in 55–82% yield with diastereomeric ratios as high as >19:1.
Xiaohan Li, Karthik S. Iyer, Ruchita R. Thakore, , ,
Published: 2 September 2021
Abstract:
Highly valued products resulting from reductive aminations utilizing shelf-stable bisulfite addition compounds of aldehydes can be made under aqueous micellar catalysis conditions. Readily available α-picolineborane serves as the stoichiometric hydride source. Recycling of the aqueous reaction medium is easily accomplished, and several applications to targets in the pharmaceutical industry are documented.
Tianyuan Zhang, Suhua Zheng, Taro Kobayashi,
Published: 2 September 2021
Abstract:
A practical protocol for the regioselective preparation of 3-phenylpropargylsilanes and 3-phenylallylsilanes in yields of 36–77 and 48–86%, respectively, from readily accessible 3-phenylpropargyl and 1-phenylallyl pivalates was developed through reductive C(sp3)–O bond cleavage. This method represents the first example of the direct application of vastly abundant calcium granules to a reductive coupling reaction. A broad range of propargylsilanes and allylsilanes are simply prepared using easy-to-handle pivalates and chlorotrimethylsilane under mild catalyst-free and additive-free conditions.
Fei Yu, Chuang Li, Chuangye Wang, , Zhong-Yan Cao
Published: 1 September 2021
Abstract:
A new, simple, yet easily accessible, (1-selenocyanatoethyl)benzene has been designed and applied as a SeCN group transfer reagent for selenocyanation of aliphatic C(sp3)–H bonds for the first time. This protocol is featured with mild reaction conditions and wide substrate scope. Control experiments reveal that a radical-group transfer mechanism might be involved.
, Lingyun Yang, Zhenzhen Dong, Junbiao Chang,
Published: 1 September 2021
Abstract:
Rhodium(III)-catalyzed annulation of 2-biphenylboronic acids with three classes of activated alkenes has been realized, leading to the synthesis of fused or bridged cyclic skeletons via transmetalation-initiated C–H activation. In the annulative coupling of 2-biphenylboronic acid with a CF3-substituted enone, the bulky cyclopentadienyl ligand (CptBu) in the catalyst proved effective to promote the reductive elimination process prior to protonolysis, affording the [4 + 2] annulated products instead of the simple 1,4-addition product. Seven-membered rings were obtained when disubstituted cyclopropenones were employed. Bridged cycles were isolated from the coupling of 2-biphenylboronic acid with benzoquinones as a result of 2-fold Michael additions. The substrate scopes were found to be broad with up to 99% yield under air-tolerant conditions.
Thibaut Duhail, Tommaso Bortolato, Javier Mateos, Elsa Anselmi, , Antonio Togni, , ,
Published: 1 September 2021
Abstract:
The first light-driven method for the α-trifluoromethoxylation of ketones is reported. Enol carbonates react with N-trifluoromethoxy-4-cyano-pyridinium, using the photoredox catalyst 4-CzIPN under 456 nm irradiation, affording the α-trifluoromethoxy ketones in ≤50% isolated yield and complete chemoselectivity. As shown by 29 examples, the reaction is general and proceeds very rapidly under batch (1 h) and flow conditions (2 min). Diverse product manipulations demonstrate the synthetic potential of the disclosed method in accessing elusive trifluoromethoxylated bioactive ingredients.
Daoyong Zhu, Wenqiang Xu, Maoping Pu, Yun-Dong Wu, ,
Published: 1 September 2021
Abstract:
Palladium catalyzes a domino Heck arylation and alkylation of nonconjugated cyclodienes to produce trans isomers of disubstituted cyclohexenes in exceptionally high enantiomeric ratios, reaching 100:1 to 200:1 in many cases. Importantly, the interactions of the two CF bonds of Josiphos and the sodium ion of malonates facilitates stereoselective allylic attack through DFT calculations and experiments. This is a new type of attractive noncovalent interactions found in organometallic catalysis.
, Valeriya S. Bolshakova, Alexander S. Peregudov, Alexander V. Chernyak, Nikita A. Slesarenko, Vitaliy Yu. Markov, Natalia S. Lukonina, Vyacheslav M. Martynenko, Ekaterina O. Sinegubova, Alexander F. Shestakov, et al.
Published: 1 September 2021
Abstract:
Here we report a reaction of the fullerene derivatives C60Ar5Cl, which enables the substitution of Cl with thiophene residues and the formation of the novel family of C1-symmetrical C60 fullerene derivatives with six functional addends C60Ar5Th. The discovered reaction provided a straightforward approach to the synthesis of previously inaccessible multifunctional water-soluble fullerene derivatives, including the compounds with antiviral activity against human immunodeficiency and influenza viruses.
Shintaro Okumura,
Published: 1 September 2021
Abstract:
We have developed a new photocatalytic umpolung reaction of carbonyl compounds to generate anionic carbinol synthons. Aromatic aldehydes or ketones reacted with carbon dioxide in the presence of an iridium photocatalyst and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole (DMBI) as a reductant under visible-light irradiation to furnish the corresponding α-hydroxycarboxylic acids through nucleophilic addition of the resulting carbinol anions to electrophilic carbon dioxide.
Zhou-Hao Zhu, Yi-Xuan Ding, Bo Wu,
Published: 1 September 2021
Abstract:
Because of the formidable development of the asymmetric reduction of tetrasubstituted olefins, an effective method is in urgent demand. Herein, through the biomimetic protocol of the coenzyme NAD(P)H, the reduction of tetrasubstituted olefin 2,3-substituted 1H-inden-1-ones has been successfully realized with the catalytic chiral NAD(P)H model CYNAM, which is hard to bring about via the common rhodium or iridium-based catalytic system, producing the corresponding products in good yield (up to 98%) with good enantioselectivity (up to 99% ee). Furthermore, the chiral bioactive molecule can be concisely synthesized from the reduced product.
Correction
Vineet K. Jakhar, Eric C. Johnson, Aditya Kavuturu, Jessica K. Heller, , Ion Ghiviriga
Published: 31 August 2021
Olivia P. Bercher, , Thomas E. Mortimer,
Published: 31 August 2021
Abstract:
Methyl groups can imbue valuable properties in organic molecules, often leading to enhanced bioactivity. To enable efficient installation of methyl groups on simple building blocks and in late-stage functionalization, a nickel-catalyzed reductive coupling of secondary Katritzky alkylpyridinium salts with methyl iodide was developed. When coupled with formation of the pyridinium salt from an alkyl amine, this method allows amino groups to be readily transformed to methyl groups with broad functional group and heterocycle tolerance.
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