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Preparation and properties of high birefringence phenylacetylene isothiocyanato-based blend liquid crystals
A series of compounds of with high birefringence containing alkoxy–phenylacetylene–isothiocyanato structure were synthesized and characterized. The chemical structures of these compounds were confirmed by FT-IR and 1H-NMR, and transition temperatures and birefringence were measured. One of these compounds with good liquid crystal property and high birefringence was mixed with host liquid crystal to form blend liquid crystal. The effects of the concentration of the compound on phase temperature range, birefringence, resistivity, dielectric anisotropy and photoelectric properties were discussed. The results showed that blend liquid crystal (with 7 wt% compound) exhibited excellent comprehensive performance.
He, Zemin,Wang, Haiyang,Zhang, Huimin,Zhang, Yongming,Zhao, Yang,Zhao, Yuzhen
(2022/04/03)

Electrochemical Fluorination of Vinyl Boronates through Donor-Stabilized Vinyl Carbocation Intermediates**
The electrochemical generation of vinyl carbocations from alkenyl boronic esters and boronates is reported. Using easy-to-handle nucleophilic fluoride reagents, these intermediates are trapped to form fully substituted vinyl fluorides. Mechanistic studies support the formation of dicoordinated carbocations through sequential single-electron oxidation events. Notably, this electrochemical fluorination features fast reaction times and Lewis acid-free conditions. This transformation provides a complementary method to access vinyl fluorides with simple fluoride salts such as TBAF.
Wigman, Benjamin,Lee, Woojin,Wei, Wenjing,Houk, Kendall N.,Nelson, Hosea M.
supporting information

(2022/02/10)

Acetylenic Replacement of Albicidin's Methacrylamide Residue Circumvents Detrimental E/Z Photoisomerization and Preserves Antibacterial Activity
The natural product albicidin is a highly potent inhibitor of bacterial DNA gyrase. Its outstanding activity, particularly against Gram-negative pathogens, qualifies it as a promising lead structure in the search for new antibacterial drugs. However, as we show here, the N-terminal cinnamoyl moiety of albicidin is susceptible to photochemical E/Z isomerization. Moreover, the newly formed Z isomer exhibits significantly reduced antibacterial activity, which hampers the development and biological evaluation of albicidin and potent derivatives thereof. Hence, we synthesized 13 different variants of albicidin in which the vulnerable para-coumaric acid moiety was replaced; this yielded photostable analogues. Biological activity assays revealed that diaryl alkyne analogues exhibited virtually undiminished antibacterial efficacy. This promising scaffold will therefore serve as a blueprint for the design of a potent albicidin-based drug.
Behroz, Iraj,Kleebauer, Leonardo,Hommernick, Kay,Seidel, Maria,Gr?tz, Stefan,Mainz, Andi,Weston, John B.,Süssmuth, Roderich D.
p. 9077 - 9086
(2021/05/27)

Synthesis and Photochemical Application of Hydrofluoroolefin (HFO) Based Fluoroalkyl Building Block
A novel fluoroalkyl iodide was synthesized on multigram scale from refrigerant gas HFO-1234yf as cheap industrial starting material in a simple, solvent-free, and easily scalable process. We demonstrated its applicability in a metal-free photocatalytic ATRA reaction to synthesize valuable fluoroalkylated vinyl iodides and proved the straightforward transformability of the products in cross-coupling chemistry to obtain conjugated systems.
Varga, Bálint,Tóth, Balázs L.,Béke, Ferenc,Csenki, János T.,Kotschy, András,Novák, Zoltán
supporting information
p. 4925 - 4929
(2021/07/01)

Cu-mediated or metal-free alkylation of gem-dibromoalkenes with tertiary, secondary and primary alkyl Grignard reagents
A novel copper-mediated or transition-metal-free alkylation of gem-dibromoalkenes with tertiary, secondary and primary alkyl Grignard reagents was described. The outcomes of these reactions were found to be highly dependent on the reaction conditions and
Deng, Yupian,Zhang, Xuxue,Liu, Chuan,Cao, Song
(2021/01/18)

Synthesis of alkynes under dry reaction conditions
An easy synthetic method was developed under dry reaction conditions for the preparation of terminal alkynes from 1,1-dibromoalkenes and in the presence of succinimide which acts as a nucleophile and proton donor. It was demonstrated with the synthesis of a broad spectrum of terminal alkynes and extended to synthesize internal alkynes under tandem reaction conditions.
Rao, Maddali L.N.,Shamim Islam, Sk
supporting information

(2021/04/19)

Design, synthesis, antileishmanial, and antifungal biological evaluation of novel 3,5-disubstituted isoxazole compounds based on 5-nitrofuran scaffolds
Nineteen 3,5-disubstituted-isoxazole analogs were synthesized based on nitrofuran scaffolds, by a [3 + 2] cycloaddition reaction between terminal acetylenes and 5-nitrofuran chloro-oxime. The compounds were obtained in moderate to very good yields (45–91%). The antileishmanial activity was assayed against the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. Alkylchlorinated compounds 14p–r were active on both the promastigote and amastigote forms, with emphasis on compound 14p, which showed strong activity against the amastigote form (IC50 = 0.6 μM and selectivity index [SI] = 5.2). In the alkyl series, compound 14o stands out with an IC50 = 8.5 μM and SI = 8.0 on the amastigote form. In the aromatic series, the most active compounds were those containing electron-donor groups, such as trimethoxy isoxazole 14g (IC50 = 1.2 μM and SI = 20.2); compound 14h, with IC50 = 7.0 μM and SI = 6.1; and compound 14j containing the 4-SCH3 group, with IC50 = 5.7 μM and SI = 10.2. In addition, the antifungal activity of 19 nitrofuran isoxazoles was evaluated against five strains of Candida (C. albicans, C. parapsilosis, C. krusei, C. tropicalis, and C. glabrata). Eleven isoxazole derivatives were active against C. parapsilosis, and compound 14o was found to be the most active (minimal inhibitory concentration [MIC] = 3.4 μM) for this strain. Compound 14p was active against all the strains tested, with an MIC = 17.5 μM for C. glabrata, lower than that of the fluconazole used as the reference drug.
Trefzger, Ozildéia S.,Barbosa, Natália V.,Scapolatempo, Renata L.,das Neves, Amarith R.,Ortale, Maria L. F. S.,Carvalho, Diego B.,Honorato, Ant?nio M.,Fragoso, Mariana R.,Shuiguemoto, Cristiane Y. K.,Perdomo, Renata T.,Matos, Maria F. C.,Chang, Marilene R.,Arruda, Carla C. P.,Baroni, Adriano C. M.
(2019/12/27)

Efficient Multigram Approach to Acetylenes and CF3-ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)
A novel approach to terminal acetylenes based on catalytic olefination reaction COR of arylaldehydes to form dichloroalkenes followed by treatment with nBuLi was elaborated. This method is atom economical and displays high yields and effectivity. The corresponding alkynes can be prepared in up to 97 % yield. One pot procedure towards CF3-ynones was elaborated to provide these products in up to 87 % yield starting from dichloroalkenes.
Muzalevskiy, Vasiliy M.,Sizova, Zoia A.,Diusenov, Arstan I.,Shastin, Alexey V.,Nenajdenko, Valentine G.
p. 4161 - 4166
(2020/07/13)

Preparation of dendritic carboranyl glycoconjugates as potential anticancer therapeutics
A series of carborane-appended glycoconjugates containing three and six glucose and galactose moieties have been synthesizedviaCu(i)-catalyzed azide-alkyne [3 + 2] click cycloaddition reaction. The carboranyl glycoconjugates containing three glucose and g
Beriha, Swaraj Kumar,Dash, Barada P.,Jena, Bibhuti Bhusan,Mahanta, Chandra Sekhara,Nayak, Bismita,Satapathy, Rashmirekha,Swain, Biswa Ranjan
p. 34764 - 34774
(2020/10/13)

Donor-acceptor substituted benzo-, naphtho- and phenanthro-fused norbornadienes
The photochromic norbornadiene/quadricyclane (NBD/QC) couple has found interest as a molecular solar thermal energy (MOST) system for storage of solar energy. To increase the energy difference between the two isomers, we present here the synthesis of a selection of benzo-fused NBD derivatives that contain an aromatic unit, benzene, naphthalene or phenanthrene, fused to one of the NBD double bonds, while the carbon atoms of the other double bond are functionalized with donor and acceptor groups. The synthesis protocols involve functionalization of benzo-fused NBDs with bromo/chloro substituents followed by a subjection of these intermediates to a cyanation reaction (introducing a cyano acceptor group) followed by a Sonogashira coupling (introducing an arylethynyl donor group, -C≡CC6H4NMe2 or -C≡CC6H4OMe). While the derivatives have good absorption properties in the visible region (redshifted relative to parent system) in the context of MOST applications, they lack the ability to undergo NBD-to-QC photoisomerization, even in the presence of a photosensitizer. It seems that loss of aromaticity of the fused aromatics is too significant to allow photoisomerization to occur. The concept of destroying aromaticity of a neighboring moiety as a way to enhance the energy density of the NBD/QC couple thus needs further structural modifications, in the quest for optimum MOST systems.
Fernandez, Lorette,Mans?, Mads,Moth-Poulsen, Kasper,Nielsen, Mogens Br?ndsted,Wang, Zhihang
(2020/01/31)

Synthesis of Phenanthrenes via Palladium-Catalyzed Three-Component Domino Reaction of Aryl Iodides, Internal Alkynes, and o-Bromobenzoic Acids
A new palladium-catalyzed domino alkyne insertion/C-H activation/decarboxylation sequence has been developed, which provides an efficient approach for synthesizing a variety of functionalized phenanthrenes in moderate to good yields. The method shows broad substrate scope and good functional group tolerance by employing readily available materials, including aryl iodides, internal alkynes, and o-bromobenzoic acids, as three-component coupling partners.
Deng, Guobo,Liang, Yun,Luo, Xiai,Yang, Xiumei,Yang, Yuan,Yang, Yuzhong,Zhou, Liwei
supporting information
p. 1223 - 1230
(2020/04/15)

Thermal decarboxylative Nazarov cyclization of cyclic enol carbonates involving chirality transfer
Decarboxylative Nazarov cyclization of chiral cyclic enol carbonates proceeded to afford chiral 2-cyclopentenones with excellent chirality transfer under thermal conditions without any catalyst. Interestingly, the thermal decarboxylative Nazarov cyclization furnished the desired product with better chirality transfer than the Lewis acid-catalyzed reaction.
Kozuma, Akane,Komatsuki, Keiichi,Saito, Kodai,Yamada, Tohru
supporting information
p. 60 - 63
(2019/12/12)

Fe-Catalyzed Selective Cyclopropanation of Enynes under Photochemical or Thermal Conditions
The nucleophilic Fe-complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the cyclopropanation of enynes to substituted propargyl cyclopropanes using diazoesters as carbene surrogates. The catalyst can be activated either thermally in the presence of catalytic amounts of 4-nitroanisole or under photochemical conditions. Cyclopropanation occurs selectively at the enyne moiety; alternative olefinic moieties remain intact.
Picher, Marie-Idrissa,Plietker, Bernd
supporting information
p. 340 - 344
(2020/01/11)

One-pot synthesis of unsymmetrical 1,3-butadiyne derivatives and their application in the synthesis of unsymmetrical 2,5-diarylthiophenes
A one-pot protocol was developed for the synthesis of unsymmetrical 1,3-butadiynes. The procedure is based on two sequential reactions: deprotection of R–C≡C–C≡C– C(Me)2OH derivatives in a retro-Favorskii reaction to furnish a terminal 1,3-butadiyne compound, which reacted with aryl iod-ides in a Sonogashira-type cross-coupling reaction catalyzed by Pd(PPh3)4 and CuI, using TBAOH as activator and toluene as solvent under reflux for 10 min. We also studied in situ thiocycli-zation of 1,3-butadiynes, leading to unsymmetrical 2,5-diaryl-thiophenes. The principal features of this method are operational simplicity, good substrate scope, very fast reaction, and high yields.
Andrade, Camila B.,Carvalho, Diego B.,Trefzger, Ozildéia S.,Kassab, Najla M.,Guerrero, Palimécio G.,Barbosa, Sandro L.,Shiguemoto, Cristiane Y. K.,Baroni, Adriano C. M.
supporting information
p. 696 - 704
(2019/01/04)

Design, synthesis and antitrypanosomatid activities of 3,5-diaryl-isoxazole analogues based on neolignans veraguensin, grandisin and machilin G
Using bioisosterism as a medicinal chemistry tool, 16 3,5-diaryl-isoxazole analogues of the tetrahydrofuran neolignans veraguensin, grandisin and machilin G were synthesized via 1,3-dipolar cycloaddition reactions, with yields from 43% to 90%. Antitrypanosomatid activities were evaluated against Trypanosoma cruzi, Leishmania (L.) amazonensis and Leishmania (V.) braziliensis. All compounds were selective for the Leishmania genus and inactive against T.?cruzi. Isoxazole analogues showed a standard activity on both promastigotes of L.?amazonensis and L.?braziliensis. The most active compounds were 15, 16 and 19 with IC50 values of 2.0, 3.3 and 9.5?μM against L.?amazonensis and IC50 values of 1.2, 2.1 and 6.4?μM on L.?braziliensis, respectively. All compounds were noncytotoxic, showing lower cytotoxicity (>250?μM) than pentamidine (78.9?μM). Regarding the structure–activity relationship (SAR), the methylenedioxy group was essential to antileishmanial activity against promastigotes. Replacement of the tetrahydrofuran nucleus by an isoxazole core improved the antileishmanial activity.
Trefzger, Ozildéia S.,das Neves, Amarith R.,Barbosa, Natália V.,Carvalho, Diego B.,Pereira, Indiara C.,Perdomo, Renata T.,Matos, Maria F. C.,Yoshida, Nidia C.,Kato, Massuo J.,de Albuquerque, Sérgio,Arruda, Carla C. P.,Baroni, Adriano C. M.
p. 313 - 324
(2018/11/30)

Tuning alkynyl-extended 9,10-dihydroanthracene-based systems into aggregation-induced emission (AIE) luminophores
A series of 9,10-bis(1,5-diphenylpenta-1,4-diyn-3-ylidene)-9,10-dihydroanthracenes (BDPPD-DHAs) carrying polar organic functional groups was synthesized through Sonogashira cross-coupling reactions. The structural and electronic properties of these BDPPD-
Johnson, Matthew A.,Tabasi, Zahra A.,Zhao, Yuming
p. 8325 - 8331
(2019/06/08)

Palladium-Catalyzed Cascade Intramolecular Cyclization and Allylation of Enynoates with Allylic Alcohols
A Pd(II)-catalyzed mild and highly regioselective 6-endo cyclization/allylation reaction of enynoates with simple allylic alcohols has been developed. Under mild reaction conditions, the vinyl palladium species generated in situ after cyclization could insert C-C double bond of allylic alcohol through cross-coupling reaction and lead to the formation of allyl pyrone via β-OH elimination. This cascade cross-coupling reaction represents a direct and atom economic methodology for the construction of novel allyl pyrones in moderate to good yields.
Qiu, Sheng-Qi,Ahmad, Tanveer,Xu, Yun-He,Loh, Teck-Peng
p. 6729 - 6736
(2019/06/14)

Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
supporting information
p. 3866 - 3870
(2019/05/24)

Functionalized Benzofurans via Microwave-Promoted Tandem Claisen-Rearrangement/5-endo-dig Cyclization
Ortho-allyloxy alkinyl benzenes undergo, upon microwave irradiation in dimethylformamide, a tandem sequence of Claisen-rearrangement and 5-endo-dig cyclization to furnish 7-allyl-substituted benzofurans. With terminal alkynes, chroman-4-ones and enaminoketones become the main products. A mechanistic proposal for this observation relies on a reaction of the starting material with the solvent dimethylformamide under the microwave conditions.
Schultze, Christiane,Schmidt, Bernd
p. 2619 - 2629
(2019/08/22)

An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
p. 2250 - 2255
(2018/02/23)

Gold-catalyzed N,O-functionalization of 1,4-diyn-3-ols with: N -hydroxyanilines to form highly functionalized pyrrole derivatives
This work describes new N,O-functionalization of 1,4-diyn-3-ols with N-hydroxyanilines to yield highly functionalized pyrrole derivatives. In a postulated mechanism, N-hydroxyaniline attacks the more electron-rich alkynes via regioselective N-attack to form unstable ketone-derived nitrones that react with their tethered alkynes via an intramolecular oxygen-transfer to form α-oxo gold carbenes. This new method is applicable to a short synthesis of a bioactive molecule, a PDE4 inhibitor.
Hsu, Yu-Chen,Hsieh, Shu-An,Li, Po-Hsuan,Liu, Rai-Shung
supporting information
p. 2114 - 2117
(2018/03/06)

Au-Catalyzed Intermolecular [2+2] Cycloadditions between Chloroalkynes and Unactivated Alkenes
The [2+2] cycloaddition is a versatile strategy for the synthesis of strained cyclobutenes of high synthetic value. In this study, two efficient intermolecular [2+2] cycloadditions between two different types of chloroalkynes and unactivated alkene are realized with gold catalysis. Of significance is that the reaction works with challenging monosubstituted unactivated alkenes, which is unprecedented in gold catalysis and scarcely documented in other metal-catalyzed/promoted reactions; moreover, the reaction exhibits excellent regioselectivities, which are much better than those reported in literature. With 1,2-disubstituted unactivated alkenes, the reaction is largely stereospecific. The cyclobutene products can be prepared in nearly gram scale and readily undergo further reactions including various cross-coupling reactions using the C(sp2)-Cl and/or C(sp2)-SPh bond, which in turn substantially broaden the scope of accessible cyclobutenes and enhance the synthetic utility of this bimolecular reaction.
Bai, Yu-Bin,Luo, Zaigang,Wang, Yuguang,Gao, Jin-Ming,Zhang, Liming
supporting information
p. 5860 - 5865
(2018/05/14)

Electrochemically modified Corey-Fuchs reaction for the synthesis of arylalkynes. the case of 2-(2,2-dibromovinyl)naphthalene
The electrochemical reduction of 2-(2,2-dibromovinyl)naphthalene in a DMF solution (Pt cathode) yields selectively 2-ethynylnaphthalene or 2-(bromoethynyl)naphthalene in high yields, depending on the electrolysis conditions. In particular, by simply changing the working potential and the supporting electrolyte, the reaction can be directed towards the synthesis of the terminal alkyne (Et4NBF4) or the bromoalkyne (NaClO4). This study allowed to establish that 2-(bromoethynyl)naphthalene can be converted into 2-ethynylnaphthalene by cathodic reduction.
Pandolfi, Fabiana,Chiarotto, Isabella,Feroci, Marta
supporting information
p. 891 - 899
(2018/04/30)

Controlled photorelease of alkynoic acids and their decarboxylative deprotection for copper-catalyzed azide/alkyne cycloaddition
A controlled photorelease of alkynoic acids from the meso-methyl BODIPY photoremovable protecting group facilitates their subsequent efficient decarboxylation to give terminal alkynes for a CuI-catalyzed azide/alkyne cycloaddition. The quantum efficiencies of the photochemical step and the kinetics of the click reaction step are reported.
Vohradská, Nikoleta,Sánchez-Carnerero, Esther M.,Pastierik, Tomá?,Mazal, Ctibor,Klán, Petr
supporting information
p. 5558 - 5561
(2018/06/04)

SO2F2-Mediated Oxidative Dehydrogenation and Dehydration of Alcohols to Alkynes
Direct synthesis of alkynes from inexpensive, abundant alcohols was achieved in high yields (greater than 40 examples, up to 95% yield) through a SO2F2-promoted dehydration and dehydrogenation process. This straightforward transformation of sp3-sp3 (C-C) bonds to sp-sp (C=C) bonds requires only inexpensive and readily available reagents (no transition metals) under mild conditions. The crude alkynes are sufficiently free of impurities to permit direct use in further transformations, as illustrated by regioselective Huisgen alkyne-azide cycloaddition reactions with PhN3 to give 1,4-substituted 1,2,3-traiazoles (16 examples, up to 92% yield) and Sonogashira couplings (10 examples, up to 77% yield).
Zha, Gao-Feng,Fang, Wan-Yin,Li, You-Gui,Leng, Jing,Chen, Xing,Qin, Hua-Li
supporting information
p. 17666 - 17673
(2019/01/04)

Preparation and Reactions of Mono- and Bis-Pivaloyloxyzinc Acetylides
Mono-pivaloyloxyzinc acetylide and bis-pivaloyloxyzinc acetylide were selectively prepared from ethynylmagnesium bromide in quantitative yields. These zinc reagents readily underwent Negishi cross-couplings with (hetero)aryl iodides or bromides as well as subsequent Sonogashira cross-couplings. 1,3-Dipolar cycloadditions of these zinc acetylides with benzylic azides produced zincated and bis-zincated triazoles which were trapped with several electrophiles. An opposite regioselectivity compared to the Cu-catalyzed click-reactions was observed.
Tüllmann, Carl Phillip,Chen, Yi-Hung,Schuster, Robin J.,Knochel, Paul
supporting information
p. 4601 - 4605
(2018/08/09)

Thermodynamic and reactivity studies of a tin corrole-cobalt porphyrin heterobimetallic complex
A heterobimetallic complex, (TPFC)Sn-Co(TAP) (TPFC = 5,10,15-tris(pentafluorophenyl)corrole, TAP = 5,10,15,20-tetrakis(p-methoxyphenyl)porphyrin), was synthesized. The complex featured a Sn-Co bond with a bond dissociation enthalpy (BDE) of 30.2 ± 0.9 kcal mol-1 and a bond dissociation Gibbs free energy (BDFE) of 21.0 ± 0.2 kcal mol-1, which underwent homolysis to produce the (TPFC)Sn radical and (TAP)CoII under either heat or visible light irradiation. The novel tin radical (TPFC)Sn, being the first four-coordinate tin radical observed at room temperature, was studied spectroscopically and computationally. (TPFC)Sn-Co(TAP) promoted the oligomerization of aryl alkynes to give the insertion products (TPFC)Sn-(CHC(Ar))n-Co(TAP) (n = 1, 2, or 3) as well as 1,3,5-triarylbenzenes. Mechanistic studies revealed a radical chain mechanism involving the (TPFC)Sn radical as the key intermediate.
Wang, Zikuan,Yao, Zhengmin,Lyu, Zeyu,Xiong, Qinsi,Wang, Bingwu,Fu, Xuefeng
p. 4999 - 5007
(2018/06/12)

Trimethylsilyl-Protected Alkynes as Selective Cross-Coupling Partners in Titanium-Catalyzed [2+2+1] Pyrrole Synthesis
Trimethylsilyl (TMS)-protected alkynes served as selective alkyne cross-coupling partners in titanium-catalyzed [2+2+1] pyrrole synthesis. Reactions of TMS-protected alkynes with internal alkynes and azobenzene under the catalysis of titanium imido comple
Chiu, Hsin-Chun,Tonks, Ian A.
supporting information
p. 6090 - 6094
(2018/05/30)

Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes
Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes are described. This redox neutral strategy offers an efficient approach to diverse biaryls, vinyl arenes and arylacetylenes. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the in situ formation of Ph3PAuIR (R = aryl, vinyl and alkynyl) species which is crucial for the activation of aryldiazonium salts.
Akram, Manjur O.,Shinde, Popat S.,Chintawar, Chetan C.,Patil, Nitin T.
supporting information
p. 2865 - 2869
(2018/05/03)

From Anilines to Aryl Ethers: A Facile, Efficient, and Versatile Synthetic Method Employing Mild Conditions
We have developed a simple and direct method for the synthesis of aryl ethers by reacting alcohols/phenols (ROH) with aryl ammonium salts (ArNMe3+), which are readily prepared from anilines (ArNR′2, R′=H or Me). This reaction proceeds smoothly and rapidly (within a few hours) at room temperature in the presence of a commercially available base, such as KOtBu or KHMDS, and has a broad substrate scope with respect to both ROH and ArNR′2. It is scalable and compatible with a wide range of functional groups.
Wang, Dong-Yu,Yang, Ze-Kun,Wang, Chao,Zhang, Ao,Uchiyama, Masanobu
supporting information
p. 3641 - 3645
(2018/03/13)

Intermolecular Desymmetrizing Gold-Catalyzed Yne–Yne Reaction of Push–Pull Diarylalkynes
Push–pull diaryl alkynes are dimerized in the presence of a cationic gold catalyst. The polarized structure of the applied starting materials enables the generation of a highly reactive vinyl cation intermediate in an intermolecular reaction. Trapping of the vinyl cation by a nucleophilic attack of the electron-poor aryl unit then leads to the selective formation of highly substituted naphthalenes in a single step and in complete atom economy.
Weingand, Vanessa,Wurm, Thomas,Vethacke, Vanessa,Dietl, Martin C.,Ehjeij, Daniel,Rudolph, Matthias,Rominger, Frank,Xie, Jin,Hashmi, A. Stephen K.
supporting information
p. 3725 - 3728
(2018/02/23)

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties
Intramolecular nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole esters is described. Efficient routes towards the synthesis of pyrrolopyrazinone, pyrrolotriazinone and pyrrolooxazinone have been developed. First, N-alkyne-substituted pyrrole ester derivatives were synthesized. Introduction of various substituents into the alkyne functionality was accomplished by a copper-catalyzed cross-coupling reaction. Nucleophilic cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with hydrazine afforded the 6-exo-dig/6-endo-dig cyclization products depending on the electronic nature of the substituents attached to the alkyne. On the other hand, cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with iodine only resulted in the formation of the 6-endo-dig cyclization product regardless of the substitution of the alkyne functionality.
Yenice, I??l,Basceken, Sinan,Balci, Metin
supporting information
p. 825 - 834
(2017/06/20)

NH2-directed C-H alkenylation of 2-vinylanilines with vinylbenziodoxolones
The first directing-group-mediated C-H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1, 3- dienes in excellent yields of up to 98% with high to perfect (Z, E) stereoselectivity. A broad substrate scope and further synthetic modifications are demonstrated.
Boelke, Andreas,Caspers, Lucien D.,Nachtsheim, Boris J.
supporting information
p. 5344 - 5347
(2017/11/07)

A practical non-metal catalytic silicon of the amino protection of the new method (by machine translation)
The invention relates to a high efficiency, mild organic silicon reagent carbon silicon key fracture of the new method. The method of this reaction to the alkali is cheap and easy to obtain metal catalyst, in order to common commercial solvent as a reaction solvent and a hydrogen source, in the air and in the under mild conditions can be successfully catalytic trimethyl aryl silicon reagent or aryl alkyne base silicon reagent selectively generating carbon silicon key cracking hydrogenation reaction, the substrate universality is wide, functional group compatibility outstanding. The first innovative to realize the non-transition metal catalyzed carbon silicon key breaking reaction, also overcome the traditional method requires the use of greatly excessive inorganic alkali or an expensive metal catalyst to the limitation of the silicon of the amino protection, for the laboratory preparation and industry in the production of the organosilicon group deprotection provides a completely new strategy. (by machine translation)
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Paragraph 0062; 0063

(2018/04/01)

Phosphinito palladium(ii) complexes as catalysts for the synthesis of 1,3-enynes, aromatic alkynes and ynones
An air-stable phosphinito palladium(ii) complex (Ph1-Phoxide) has been found to be an efficient catalyst in the formation of C-C bonds. The coupling of terminal alkynes formed gem-1,3-enynes as the only reaction products. Aromatic alkynes can be synthesized from the coupling of terminal alkynes and haloaromatic compounds (Sonogashira coupling). The phosphinito palladium(ii) complex also catalyses the coupling between acyl chlorides and terminal alkynes (Sonogashira coupling), furnishing ynones in excellent yields.
Islas,Cárdenas,Gavi?o,García-Ríos,Lomas-Romero,Morales-Serna
p. 9780 - 9789
(2017/02/15)

Four-Step Total Synthesis of Selaginpulvilin D
An extremely concise total synthesis of a potent phosphodiesterase-4 inhibitory natural product, selaginpulvilin D, is reported. The synthesis features a one-pot, 3-fold electrophilic aromatic substitution sequence to assemble a 9,9-diarylfluorene core. T
Sowden, Madison J.,Sherburn, Michael S.
supporting information
p. 636 - 637
(2017/02/10)

Synthesis, photophysical and concentration-dependent tunable lasing behavior of 2,6-diacetylenyl-functionalized BODIPY dyes
2,6-Diacetylenyl- and 2,6-bis(arylacetylenyl)-functionalized pentamethyl-difluoroborondipyrromethene (BODIPY) derivatives, namely, PBDP1 and PBDP2-4 (aryl = phenyl, 4-methoxyphenyl, or 4-cyanophenyl), respectively, which exhibit extended π-conjugation, were synthesized and characterized by various spectroscopic methods. Significant bathochromic shifts in both absorption and emission were observed upon modifying the structure of the BODIPY core via the strategy of extending its π-conjugation. The derivatives displayed efficient emission in the yellow-to-red spectral region, with a high fluorescence quantum yield and a relatively large Stokes shift. Under conditions of transverse pumping in a cuvette, PBDP1 and PBDP2 exhibited highly efficient and stable laser activity for up to 180 and 110 minutes of continuous irradiation, respectively. Amplified spontaneous emission (FWHM of ca. 2.5 nm) with an efficiency of 41% and 36% was achieved for PBDP1 and PBDP2, respectively, in toluene, which had tunable ranges of 561 to 580 nm and 602 to 617 nm, respectively, on irradiation with a Q-switched Nd:YAG laser at 532 nm. The lasing properties of PBDP3 and PBDP4, which contain electron-donating (-OMe) and electron-withdrawing (-CN) arylacetylenyl moieties, respectively, were also investigated. A corresponding digold(i) diacetylide organometallic complex, namely, (PPh3)Au-C≡C-BODIPY-C≡C-Au(PPh3) (PBDP5) was also synthesized and characterized to study the effect of Au(i). PBDP5 exhibited phosphorescence in the vis-NIR region centered at 751 nm at 77 K owing to heavy-atom-induced intersystem crossing.
Maity, Apurba,Sarkar, Anirban,Sil, Amit,B. N., Shivakiran Bhaktha,Patra, Sanjib K.
supporting information
p. 2296 - 2308
(2017/03/22)

Synthesis of ent-[3]-Ladderanol: Development and Application of Intramolecular Chirality Transfer [2+2] Cycloadditions of Allenic Ketones and Alkenes
An enantioselective synthesis of ent-[3]-ladderanol is presented. The ladderanes are an interesting class of molecules for their unique structure of fused cyclobutane rings as well as their perceived biological function of organism protection. The route h
Line, Nathan J.,Witherspoon, Brittany P.,Hancock, Erin N.,Brown, M. Kevin
supporting information
p. 14392 - 14395
(2017/10/24)

Palladium-catalyzed tandem C-H functionalization/cyclization strategy for the synthesis of 5-hydroxybenzofuran derivatives
A palladium-catalyzed benzoquinone C-H functionalization/ cyclization strategy with terminal alkynes was employed for the synthesis of some biologically relevant 2, 3-disubstituted 5-hydroxybenzofuran derivatives. The benzoquinone acts as a reactant as well as an oxidant. During the process, an additional alkyne functionality can be introduced at the C3 position of the benzofuran. Base, ligand, and external oxidant are not required in this protocol.
Ichake, Sachin S.,Konala, Ashok,Kavala, Veerababurao,Kuo, Chun-Wei,Yao, Ching-Fa
supporting information
p. 54 - 57
(2017/11/28)

Na2S-mediated synthesis of terminal alkynes from: Gem -dibromoalkenes
The Na2S-mediated facile synthesis of terminal alkynes from gem-dibromoalkenes, at 20/40 °C under open flask conditions has been developed. Various precursors derived from heteroaromatic/aromatic/aliphatic aldehydes were found compatible. The reaction is proposed to proceed through the Fritsch-Buttenberg-Wiechell (FBW) rearrangement involving the corresponding vinyl carbene. Using mild reaction conditions with inexpensive Na2S·9H2O under air atmosphere has significant advantages over earlier routes.
Singh, Radhey M.,Nandini, Durgesh,Bharadwaj, Kishor Chandra,Gupta, Tanu,Singh, Raj Pal
supporting information
p. 9979 - 9982
(2017/12/26)

Efficient one-pot synthesis of 1-chlorovinyl p-tolyl sulfoxides from aldehydes and ketones by the Horner-Wadsworth-Emmons reaction
A variety of 2-monosubstituted and 2,2-disubstituted 1-chlorovinyl p-tolyl sulfoxides was synthesized through a one-pot procedure by the Horner-Wadsworth-Emmons reaction of carbonyl compounds with [chloro(diethoxyphosphoryl)(p-tolylsulfinyl)methyl]lithium, which was generated from diethyl chlorophosphate, chloromethyl p-tolyl sulfoxide, and lithium diisopropylamide in advance. The in situ-prepared sulfoxides were directly converted into alkynes via the sulfoxide/magnesium exchange reaction with i-PrMgCl and the subsequent Fritsch-Buttenberg-Wiechell rearrangement of the resulting magnesium alkylidene carbenoids.
Kimura, Tsutomu,Kobayashi, Gen,Ijima, Shiori,Saito, Sae,Imafuji, Aki,Satoh, Tsuyoshi
(2017/10/27)

Calcium carbide catalytically activated with tetra-: N -butyl ammonium fluoride for Sonogashira cross coupling reactions
We report a novel method for the direct synthesis of mono- and bis-arylated alkynes utilizing catalytically activated CaC2 as the alkyne component. This fluoride-activated cross coupling reaction provides advantages over existing methods regarding operational simplicity, use of readily available starting materials, and low cost.
Hosseini, Abolfazl,Pilevar, Afsaneh,Hogan, Eimear,Mogwitz, Boris,Schulze, Anne S.,Schreiner, Peter R.
p. 6800 - 6807
(2017/08/22)

One-Pot, Atom and Step Economy (PASE) Assembly of Trifluoromethylated Pyrimidines from CF3-Ynones
A highly efficient synthetic method for the preparation of of 6-trifluoromethylated pyrimidines was developed. The reaction of CF3-substituted ynones and nitrogen 1,3-bis(nucleophile)s was employed for the one-pot assembly of the pyrimidine core. The cascade route proceeded through an aza-Michael addition, intramolecular cyclization, and dehydration reaction sequence to give the target heterocycles in excellent yields (up to 97 %). When acetamidine was used as the bis(nucleophile), the unexpected addition of two equivalents of the CF3-substituted ynone to the acetamidine was observed.
Romanov, Alexey R.,Rulev, Alexander Yu.,Ushakov, Igor A.,Muzalevskiy, Vasiliy M.,Nenajdenko, Valentine G.
p. 4121 - 4129
(2017/08/07)

Transition-Metal-Free Alkynylation of 2-Oxindoles through Radical-Radical Coupling
An effective transition-metal-free approach for the synthesis of 3-alkynyl-2-oxindoles through a radical-radical coupling process was developed. The reaction was general with respect to 2-oxindoles and iodoalkynes and provided the desired products bearing a quaternary center at C3 in good to excellent yields, making this method synthetically viable and attractive for the synthesis of spiro and fused 2-oxindole derivatives.
Huang, Hong-Yan,Cheng, Liang,Liu, Jie-Jie,Wang, Dong,Liu, Li,Li, Chao-Jun
p. 2656 - 2663
(2017/03/14)

Control of the Regioselectivity in Cobalt- versus Ruthenium-Catalyzed Alder-ene Reaction of Unsymmetrical 1,3-Diynes
The Alder-ene reaction of trialkylsilyl-substituted 1,3-butadiynes with terminal alkenes was investigated utilizing a cobalt-based catalyst, and the results were compared with Alder-ene rections catalyzed by the [CpRu(H3CCN)3]PF6 catalyst. Obviously, the two catalysts gave complementary results of yn-dienes differing in the site where the new carbon-carbon bond was formed. Of particular interest are observations concerning the double bond migration within the alkene component. While simple alkenes gave exclusively the E-configuration, the application of 3-buten-1-ol resulted in the corresponding Z-double bond, indicating that the hydroxyl group acts as donor coordinating to the cobalt center and thereby altering the reaction pathway.
Weber, Sebastian M.,Hilt, Gerhard
supporting information
p. 564 - 567
(2017/02/10)

Containing diphenylacetylene cyclopentadienyl iron salt such two-photon absorbing material and its preparation method
The invention relates to three cyclopentadienyl iron salt two-photon absorption materials having a diphenylacetylene group and a preparation method thereof; a diphenylacetylene structure and a cationic cyclopentadienyl iron receptor are jointly composed of a D-(pi)-A type two-photon absorption functional group, and thus the three synthesized novel cyclopentadienyl iron salts have a strong two-photon absorption ability at 532 nm, and has great application value in the two-photon photoetching field when used as the two-photon absorption type cationic photo-initiator.
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Paragraph 0079; 0080

(2017/08/25)

Reaction discovery using acetylene gas as the chemical feedstock accelerated by the stop-flow micro-tubing reactor system
Acetylene gas has been applied as a feedstock under transition-metal catalysis and photo-redox conditions to produce important chemicals including terminal alkynes, fulvenes, and fluorinated styrene compounds. The reaction discovery process was accelerated through the use of stop-flow micro-tubing reactors. This reactor prototype was developed by joining elements from both continuous micro-flow and conventional batch reactors, which was convenient and effective for gas/liquid reaction screening. Notably, the developed transformations were either inefficient or unsuccessful in conventional batch reactors. Its success relies on the unique advantages provided by this stop-flow micro-tubing reactor system.
Xue, Fei,Deng, Hongping,Xue, Chengwen,Mohamed, Dara Khairunnisa Binte,Tang, Karen Yuanting,Wu, Jie
p. 3623 - 3627
(2017/07/11)

Heterocyclic compound and organic light-emitting device including the same
A heterocyclic compound represented by Formula 1 below, and an organic light-emitting device including the heterocyclic compound:
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(2017/08/26)

Rapid access to unsymmetrical tolanes and alkynones by sequentially palladium-catalyzed one-pot processes
Alkynones as well as unsymmetrically substituted tolanes (diarylalkynes) can be rapidly generated in a one-pot fashion via sequential palladium catalysis. Terminal alkynes, formed in situ by protecting-group free palladium-catalyzed coupling of aryl iodides with ethynyl magnesium bromide, are subsequently transformed by Sonogashira coupling with aryl halides or aroyl chlorides to furnish unsymmetrically substituted alkynes in good to excellent yields.
G?tzinger, Alissa C.,Müller, Thomas. J. J.
supporting information
p. 3498 - 3500
(2016/04/19)

Synthesis and Antitrypanosomastid Activity of 1,4-Diaryl-1,2,3-triazole Analogues of Neolignans Veraguensin, Grandisin and Machilin G
Sixteen 1,4-diaryl-1,2,3-triazole compounds derived from the natural products veraguensin, grandisin and machilin G were synthesized, with yields of 78-92percent. Biological activity tests against Leishmania amazonensis promastigotes showed that three of these compounds were the most active, with maximum inhibitory concentration (IC50 ) values of 1.1, 3.71 and 7.23 μM. One compound was highly active against Leishmania infantum, with an IC50 value of 5.2 μM, and one derivative showed an IC50 value of 28.6 μM against Trypanosoma cruzi trypomastigotes. Regarding structureactivity relationship (SAR), hybrid 1,2,3-triazolic compounds containing a methylenedioxy group, showed the best antileishmanial and antitrypanosomal activities.
Cassamale, Tatiana B.,Costa, Eduarda C.,Carvalho, Diego B.,Cassemiro, Nadla S.,Tomazela, Carolina C.,Marques, Maria C. S.,Ojeda, Mariáh,Matos, Maria F. C.,Albuquerque, Sérgio,Arruda, Carla C. P.,Baroni, Adriano C. M.
p. 1217 - 1228
(2016/08/25)