- Rhodium-Catalyzed Annulation of Phenacyl Ammonium Salts with Propargylic Alcohols via a Sequential Dual C-H and a C-C Bond Activation: Modular Entry to Diverse Isochromenones
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Given their omnipresence in natural products and pharmaceuticals, isochromenone congeners are one of the most privileged scaffolds to synthetic chemists. Disclosed herein is a dual (ortho/meta) C-H and C-C activation of phenacyl ammonium salts (acylammonium as traceless directing group) toward annulation with propargylic alcohols to accomplish rapid access for novel isochromenones by means of rhodium catalysis from readily available starting materials. This operationally simple protocol features broad substrate scope and wide functional group tolerance. Importantly, the protocol circumvents the need of any stoichiometric metal oxidants and proceeds under aerobic conditions.
- Nanubolu, Jagadeesh Babu,Reddy Singam, Maneesh Kumar,Sridhar Reddy, Maddi,Suresh, Vavilapalli,Suri Babu, Undamatla
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supporting information
p. 7888 - 7893
(2021/10/25)
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- Sodium-metal-promoted reductive 1,2-syn-diboration of alkynes with reduction-resistant trimethoxyborane
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Reductive 1,2-diboration of alkynes has been accomplished by means of sodium dispersion in the presence of trimethoxyborane as a reduction-resistant boron electrophile. Two boron moieties can be introduced onto alkynes with excellent syn selectivity to afford the corresponding (Z)-1,2-diborylalkenes. Bis(borate) species generated in situ can be involved in one-pot Suzuki-Miyaura arylation, formal arylboration of alkynes thus being executed.
- Fukazawa, Mizuki,Ito, Shiori,Nogi, Keisuke,Takahashi, Fumiya,Yorimitsu, Hideki
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p. 1171 - 1179
(2020/10/18)
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- Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids
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It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72–99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.
- Orha, László,Tukacs, József M.,Kollár, László,Mika, László T.
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supporting information
p. 2907 - 2913
(2019/12/14)
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- Metal-Free Regioselective Chloroazidation of Internal Alkynes
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A metal-free, room temperature protocol for the regioselective chloroazidation of internal alkynes is disclosed. The reactions of internal alkynes with trimethylsilyl azide (TMSN3) in the presence of 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) afforded the corresponding chloroazidoalkenes in good yields. This reaction has good functional group tolerance and is operationally simple.
- Huang, Bin,Liffert, Raphael,Linden, Anthony,Gademann, Karl
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supporting information
p. 981 - 984
(2019/01/04)
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- Copper-Catalyzed Radical 1,4-Difunctionalization of 1,3-Enynes with Alkyl Diacyl Peroxides and N-Fluorobenzenesulfonimide
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Many reactions involving allenyl ion species have been studied, but reactions involving allenyl radicals are less well understood, perhaps because of the inconvenience associated with the generation of short-lived allenyl radicals. We describe here a versatile method for the generation of allenyl radicals and their previously unreported applications in the intermolecular 1,4-carbocyanation and 1,4-sulfimidocyanation of 1,3-enynes. With the assistance of the trifunctional reagents, alkyl diacyl peroxides or N-fluorobenzenesulfonimide, a range of synthetically challenging multisubstituted allenes can be prepared with high regioselectivity. These multisubstituted allenes can be easily transformed into synthetically useful structures such as fluorinated vinyl cyanides, lactones, functionalized allenyl amides, 1-aminonaphthalenes, and pyridin-2(1H)-ones, and several novel transformations are reported. The results of radical scavenger and radical clock experiments are consistent with the proposed allenyl radical pathway. Density functional theory (DFT) and IR spectroscopy studies suggest the formation of an isocyanocopper(II) species in the ligand exchange step. On the basis of the results of IR, DFT, and diastereoselectivity studies, an isocyanocopper(II)/copper(I) catalytic cycle is proposed, which differs from the previously considered Cu(III) mechanism in cyanation reactions.
- Zhu, Xiaotao,Deng, Weili,Chiou, Mong-Feng,Ye, Changqing,Jian, Wujun,Zeng, Yuehua,Jiao, Yihang,Ge, Liang,Li, Yajun,Zhang, Xinhao,Bao, Hongli
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supporting information
p. 548 - 559
(2019/01/04)
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- Visible-light-driven selective alkenyl C-P bond cleavage of allenylphosphine oxides
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An efficient method for highly selective alkenyl C-P bond cleavage, enabled by organic dyes and visible-light irradiation, was developed. This novel protocol involves a highly regioselective radical pathway initiated by singlet oxygen, affording diverse a
- Wei, Kai,Luo, Kai,Liu, Fang,Wu, Lei,Wu, Li-Zhu
-
supporting information
p. 1994 - 1998
(2019/03/29)
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- Synthesis of 4-Oxoisoxazoline N-Oxides via Pd-Catalyzed Cyclization of Propargylic Alcohols with tert-Butyl Nitrite
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A cyclization of propargylic alcohols with tert-butyl nitrite at room temperature in air was achieved using Pd(OAc)2 as catalyst. The first reported 4-oxoisoxazoline N-oxides could be directly accessed from a range of multisubstituted propargylic alcohols in moderate to excellent yields under mild conditions. Density functional theory calculations indicated that the reaction proceeds through a palladium-catalyzed NO2 addition that efficiently generates a ketoxime radical, which eventually produces 4-oxoisoxazoline N-oxide.
- Feng, Kai-Wen,Ban, Yong-Liang,Yuan, Pan-Feng,Lei, Wen-Long,Liu, Qiang,Fang, Ran
-
supporting information
p. 3131 - 3135
(2019/05/10)
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- Palladium(II)/Lewis acid cocatalyzed oxidative annulation of 2-alkenylanilines and propargylic esters: An access to benzo[ b]azepines
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An attractive approach to valuable yet synthetically challenging benzo[b]azepines was established via palladium(II)/Lewis acid cocatalyzed oxidative [5 + 2] annulation of readily available 2-alkenylanilines and propargylic esters. The protocol features mild reaction conditions and good functional group tolerance, constituting an array of benzo[b]azepines in yields of 30-75%.
- Qiao, Hong,Zhang, Shengjun,Li, Kangkang,Cao, Zhengqiang,Zeng, Fanlong
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p. 10843 - 10851
(2019/09/12)
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- Neighboring Carbonyl Group Assisted Hydration of Unsymmetrical Aryl Alkynes Overriding Regular Selectivity
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A mild and highly regioselective gold-catalyzed hydration of γ-acetoxy aryl alkynes leading to anti-Markovnikov products by the assistance of a neighboring carbonyl group is presented. The reaction procedure operates under room temperature conditions with
- Mendhekar, Kishor L.,Pradhan, Tapas R.,Mallampudi, N. Arjunreddy,Mohapatra, Debendra K.
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p. 5787 - 5797
(2019/08/21)
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- Hydrotalcite-supported palladium nanoparticles as catalysts for the hydroarylation of carbon-carbon multiple bonds
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Palladium nanoparticles supported on Mg/Ca hydrotalcites catalyze the hydroarylation reaction of different alkynes and alkenes with aryl iodides under air in MeCN. The reaction of tertiary propargylic alcohols (1) with aryl iodides (2) yields, stereoselectively, γ,γ-diarylallylic alcohols (3) in moderate to high yields and high selectivity. Also, the HT/Pd hydroarylation reaction with aryl iodides was attempted on norbornene and α,β-unsaturated ketones affording, respectively, exo-aryl bicyclo[2.2.1]heptanes and β-aryl ketones in moderate to high yields. All the reactions described benefit from using a heterogeneous catalyst with evident advantages in terms of reaction purification and recyclability of the catalyst.
- Di Nicola,Arcadi,Gallucci,Mucciante,Rossi
-
supporting information
p. 1952 - 1957
(2018/02/09)
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- Rhodium-Catalyzed Highly Regio- and Enantioselective Hydrogenation of Tetrasubstituted Allenyl Sulfones: An Efficient Access to Chiral Allylic Sulfones
-
A highly regio- and enantioselective hydrogenation of challenging tetrasubstituted allenyl sulfones has been developed, affording chiral allylic sulfones in good yields with excellent regio- and enantioselectivities (up to 99 % yield and 99 % ee). This me
- Long, Jiao,Shi, Liyang,Li, Xiong,Lv, Hui,Zhang, Xumu
-
supporting information
p. 13248 - 13251
(2018/09/21)
-
- DBU-promoted carbonylative synthesis of 1,3-oxathiolan-2-ones from propargylic alcohols with TFBen as the CO source
-
A DBU-promoted carbonylative cyclization of propargylic alcohols with sulfur was developed. Various 1,3-oxathiolan-2-ones were produced in 61-98% yields under mild conditions in the absence of metal catalysts. TFBen (benzene-1,3,5-triyl triformate) as an efficient and solid CO surrogate and S8 as an ideal sulfur source were employed and incorporated.
- Ying, Jun,Zhou, Chao,Wu, Xiao-Feng
-
supporting information
p. 1065 - 1067
(2018/02/22)
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- 1,8-Diazabicyclo[5.4.0]undec-7-ene-Catalyzed Carbonylative Cyclization of Propargylic Alcohols with Elemental Sulfur
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A carbonylation procedure involving the cyclization of propargylic alcohols with elemental sulfur was developed. With 1,8-diazabicyclo[5.4.0]undec-7-ene as the catalyst, elemental sulfur and carbon monoxide are activated and incorporated into propargylic
- Hu, Yuya,Yin, Zhiping,Werner, Thomas,Spannenberg, Anke,Wu, Xiao-Feng
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p. 1274 - 1276
(2018/03/21)
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- Direct Substitution of Secondary and Tertiary Alcohols to Generate Sulfones under Catalyst- and Additive-Free Conditions
-
An environmentally benign protocol that affords propargylic sulfones containing highly congested carbon centers from easily accessible alcohols and sulfinic acids with water as the only byproduct is reported. The reaction proceeded via an in situ dehydrative cross-coupling process by taking advantage of the synergetic actions of multiple hydrogen bonds rather than relying on an external catalyst and/or additives to achieve high product distribution.
- Liu, Yanan,Xie, Peizhong,Sun, Zuolian,Wo, Xiangyang,Gao, Cuiqing,Fu, Weishan,Loh, Teck-Peng
-
supporting information
p. 5353 - 5356
(2018/09/13)
-
- Synthesis of Isoquinolines through IrIII-Catalyzed C–H Activation/Annulation from Benzimidates with Hydroxylisopropylalkynes
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An IrIII-catalyzed cascade reaction consisting of C–H activation/annulation of benzimidates with hydroxylisopropylalkynes is reported. A broad range of isoquinolines has been prepared in one step with good functiona-group tolerance and high eff
- Liu, Mingliang,Gong, Wanchun,You, Erli,Zhang, Haizhen,Shi, Lei,Cao, Weiguo,Shi, Jingjing
-
supporting information
p. 4991 - 4995
(2018/10/05)
-
- Tert-butoxy rare earth/sodium impurity bimetallic complex, as well as preparation method and use thereof
-
The invention discloses a tert-butoxy rare earth/sodium hetero-bimetallic complex as well as a preparation method and use thereof. The molecular formula of the tert-butoxy rare earth/sodium hetero-bimetallic complex is LnNa8[OC(CH3)3]10(OH), and Ln repres
- -
-
Paragraph 0053-0054
(2017/07/13)
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- On the Distribution of Linear versus Angular Naphthalenes in Aromatic Tetradehydro-Diels–Alder Reactions – Effect of Linker Structure and Steric Bulk
-
We report here a systematic study of the aromatic tetradehydro-Diels–Alder (Ar-TDDA) reaction to elucidate the factors that have significant effects on the distribution of linear and angular naphthalene products. Two factors were studied, that is, the nat
- Chinta, Bhavani Shankar,Baire, Beeraiah
-
supporting information
p. 3381 - 3385
(2017/06/29)
-
- Cyclic eneyne compound and synthesis method thereof
-
The invention relates to a cyclic eneyne compound and a preparation method thereof. The chemical formula is described in the description, wherein substituent R is any one of phenyl or p-methylphenyl or isohexyl or n-heptyl, ring is a five-membered ring or
- -
-
Paragraph 0031-0033
(2017/10/05)
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- Dendrimer-encapsulated Pd(0) nanoparticles immobilized on nanosilica as a highly active and recyclable catalyst for the copper- and phosphine-free Sonogashira-Hagihara coupling reactions in water
-
This study demonstrates a new synthetic strategy for the preparation of porous SiO2 for catalytic applications using natural and waste materials from rice husks as the source of biosilica. Biogenic porous silica nanoparticles with a mean diameter of 45 nm were successfully prepared from rice husk (RH) biomass via a new multistep method. During the first step, sodium silicate is extracted from rice husks. Then, cetyltrimethylammonium bromide (CTAB), HCl, and HOAc were added into sodium silicate solution, and the resulting mixture was sonicated. After the hydrothermal reaction, the collected samples were calcinated to obtain silica nanoparticles. Then, dendrimer-encapsulated Pd(0) nanoparticles supported on nano-silica with surface amino groups were fabricated. These materials are prepared by sequestering palladium ions within dendrimers followed by chemical reduction to yield the corresponding zero-valent palladium nanoparticles. The synthesized nanostructures were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), dynamic light scattering (DLS), N2 adsorption-desorption isotherm analysis, UV-vis spectroscopy and elemental analysis. The morphologies of the catalyst were characterized using a field emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM). Also, its Pd content was determined by using an inductively coupled plasma (ICP) analyzer. This catalytic system was used as an efficient catalyst for Sonogashira reaction of aryl halides with alkynes under copper and phosphine ligand-free conditions in water. The catalyst was regenerated for five cycles of reaction without any significant loss in its activity. Also, the analysis of the reaction mixture by the ICP technique showed that the leaching of the catalyst was negligible.
- Esmaeilpour, Mohsen,Sardarian, Alireza,Javidi, Jaber
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p. 4005 - 4019
(2016/06/13)
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- Fluoride-assisted activation of calcium carbide: A simple method for the ethynylation of aldehydes and ketones
-
The fluoride-assisted ethynylation of ketones and aldehydes is described using commercially available calcium carbide with typically 5 mol % of TBAF·3H2O as the catalyst in DMSO. Activation of calcium carbide by fluoride is thought to generate an acetylide "ate"-complex that readily adds to carbonyl groups. Aliphatic aldehydes and ketones generally provide high yields, whereas aromatic carbonyls afford propargylic alcohols with moderate to good yields. The use of calcium carbide as a safe acetylide ion source along with economic amounts of TBAF·3H2O make this procedure a cheap and operationally simple method for the preparation of propargylic alcohols.
- Hosseini, Abolfazl,Seidel, Daniel,Miska, Andreas,Schreiner, Peter R.
-
supporting information
p. 2808 - 2811
(2015/06/16)
-
- A tyrosine-rich peptide induced flower-like palladium nanostructure and its catalytic activity
-
A specifically designed peptide, Tyr-Tyr-Ala-His-Ala-Tyr-Tyr (YYAHAYY), induced the formation of a flower-like palladium (Pd) nanostructure by controlling the size and shape of nanoparticles (NPs). The flower-shaped Pd NPs showed excellent catalytic activ
- Kim, Young-O,Jang, Hyung-Seok,Kim, Yo-Han,You, Jae Myoung,Park, Yong-Sun,Jin, Kyoungsuk,Kang, Onyu,Nam, Ki Tae,Kim, Jung Won,Lee, Sang-Myung,Lee, Yoon-Sik
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p. 78026 - 78029
(2015/09/28)
-
- Microwave-Assisted Organocatalyzed Rearrangement of Propargyl Vinyl Ethers to Salicylaldehyde Derivatives: An Experimental and Theoretical Study
-
The microwave-assisted imidazole-catalyzed transformation of propargyl vinyl ethers (PVEs) into multisubstituted salicylaldehydes is described. The reaction is instrumentally simple, scalable, and tolerates a diverse degree of substitution at the propargylic position of the starting PVE. The generated salicylaldehyde motifs incorporate a broad range of topologies, spanning from simple aromatic monocycles to complex fused polycyclic systems. The reaction is highly regioselective and takes place under symmetry-breaking conditions. The preparative power of this reaction was demonstrated in the first total synthesis of morintrifolin B, a benzophenone metabolite isolated from the small tree Morinda citrifolia L. A DFT study of the reaction was performed with full agreement between calculated values and experimental results. The theoretically calculated values support a domino mechanism comprising a propargyl Claisen rearrangement, a [1,3]-H shift, a [1,7]-H shift (enolization), a 6π electrocyclization, and an aromatization reaction.
- Tejedor, David,Cotos, Leandro,Márquez-Arce, Daniel,Odriozola-Gimeno, Mikel,Torrent-Sucarrat, Miquel,Cossío, Fernando P.,García-Tellado, Fernando
-
supporting information
p. 18280 - 18289
(2015/12/24)
-
- An approach to the selenobromination of aryl(thienyl)alkynes: Access to 3-bromobenzo[b]selenophenes and selenophenothiophenes
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A novel approach for the cyclization of arylalkynes with selenium(IV) bromide prepared in situ has been elaborated. The use of an alkene additive as a bromine scavenger provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes. Reactions can be performed open to air without the use of moisture-sensitive reagents, anhydrous solvents, or an inert atmosphere. Selenobromination of ethynylthiophenes has been applied for the preparation of selenopheno[3,2-b]- and selenopheno[2,3-b]thiophenes. The molecular structures of representative derivatives have been confirmed by X-ray crystallographic analysis. The use of an alkene additive as a bromine scavenger under selenobromination conditions provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes in moderate to high yields. The reactions are not moisture-sensitive and do not require an inert atmosphere. Selenobromination of ethynylthiophenes enables the preparation of selenopheno[b]thiophenes. Copyright
- Paegle, Edgars,Belyakov, Sergey,Arsenyan, Pavel
-
supporting information
p. 3831 - 3840
(2014/06/24)
-
- Pd/tetraphosphine catalytic system for Cu-free Sonogashira reaction "on water"
-
An efficient copper-free Sonogashira coupling reaction was performed on water at 100 °C with N,N,N′,N′-tetra(diphenylphosphinomethyl) pyridine-2,6-diamine (1) as a ligand, [Pd(η3-C3H 5)Cl]2 as a catalyst precursor and K3PO 4 as a base. Both aryl and heteroaryl halides were successfully alkynylated in this system, and a high turnover number (TON) up to 860000 was obtained with a catalyst loading as low as 1 ppm.
- Zhou, Rong,Wang, Wei,Jiang, Zhi-Jie,Fu, Hai-Yan,Zheng, Xue-Li,Zhang, Chun-Chun,Chen, Hua,Li, Rui-Xiang
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p. 746 - 751
(2014/03/21)
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- A Lewis acid/metal amide hybrid as an efficient catalyst for carbon-carbon bond formation
-
While Lewis acids and metal amides are among the most frequently used metal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitro
- Yamashita, Yasuhiro,Saito, Yuki,Imaizumi, Takaki,Kobayashi, Shu
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p. 3958 - 3962
(2014/10/15)
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- Alkynylation of aldehydes and ketones using the Bu4NOH/H 2O/DMSO catalytic composition: A wide-scope methodology
-
The Favorsky reaction of a wide range of aldehydes and ketones with alkynes has been implemented under mild conditions (5-20 C). Using a Bu 4NOH/H2O/DMSO catalytic system, propargylic alcohols are formed cleanly in 39-93% (mostly 72-93%) yields and with ca. 100% selectivity. The method is suitable for aliphatic, aromatic, and heteroaromatic aldehydes and ketones, and for aliphatic, aromatic, and functionalized acetylenes. Thus, this represents the most general and efficient protocol to achieve the Favorsky reaction. Copyright
- Schmidt, Elena Yu.,Cherimichkina, Natalia A.,Bidusenko, Ivan A.,Protzuk, Nadezhda I.,Trofimov, Boris A.
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p. 4663 - 4670
(2014/08/05)
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- Iron-catalyzed reductive cyclization of 1,6-enynes
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A precatalyst of FeCl2 and iminopyridine was activated in situ by a combination of diethylzinc and magnesium bromide etherate; it catalyzed the reductive cyclization of 1,6-enynes to give pyrrolidine and tetrahydrofuran derivatives from N-and O
- Lin, Aijun,Zhang, Zhi-Wei,Yang, Jiong
-
supporting information
p. 386 - 389
(2014/04/03)
-
- Gold-catalyzed oxidative reactions of propargylic carbonates involving 1,2-carbonate migration: Stereoselective synthesis of functionalized alkenes
-
A gold-catalyzed oxidative reaction of propargylic carbonates or acetates using 3,5-dichloropyridine as the oxidant has been developed. The reaction provides efficient access to α-functionalized-α,β-unsaturated ketones with excellent regio- and diastereoc
- Sun, Ning,Chen, Ming,Liu, Yuanhong
-
p. 4055 - 4067
(2014/05/20)
-
- Mild conversion of propargylic alcohols to α,β-unsaturated enones in ionic liquids (ILs); A new 'metal free' life for the Rupe rearrangement
-
A mild and selective transition metal free protocol for the conversion of propargylic alcohols to cyclic and acyclic α,β-unsaturated enones via the Rupe rearrangement is reported. The method utilizes the Br?nsted acidic ionic liquid [BMIM-SO3H][OTf] as catalyst and [BMIM][PF 6] as solvent and offers the potential for recycling and reuse of the IL solvent. The feasibility to synthesize bicyclic fused cyclopentenone derivatives via a Rupe → Aldol → Nazarov sequence utilizing this protocol has also been demonstrated.
- Nandi, Ganesh C.,Rathman, Benjamin M.,Laali, Kenneth K.
-
supporting information
p. 6258 - 6263
(2013/10/22)
-
- Synthesis of 2,3-diiodoindenes and their applications in construction of 13H-indeno[1,2-l]phenanthrenes
-
A series of 2,3-diiodoindene were synthesized at first, and 13H-indeno[1,2-l]phenanthrenes were then constructed via a Suzuki coupling reaction and subsequently a Scholl reaction. Structures of synthesized compounds were fully characterized by 1H NMR, 13C NMR, and HRMS. Their photophysical properties, such as UV-vis and FL spectra were investigated, and electronic properties were theoretically calculated by the software of Gaussian 03. The results suggested that these modified indene and indenophenanthrene compounds might have potential applications as light emitting materials.
- Zhou, Chao,Chen, Xiaopeng,Lu, Ping,Wang, Yanguang
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supporting information; experimental part
p. 2844 - 2850
(2012/05/05)
-
- Highly stereoselective and scalable synthesis of trans -fused octahydrocyclohepta[ b ]pyrrol-4(1 H)-ones via the aza-Cope-Mannich rearrangement in racemic and enantiopure forms
-
We have developed an efficient and stereoselective route to trans-fused octahydrocyclohepta[b]pyrrol-4(1H)-ones. The key features of our synthesis include the regioselective epoxide ring-opening of alkynyl oxiranes and a stereoselective aza-Cope-Mannich r
- Belov, Dmitry S.,Lukyanenko, Evgeny R.,Kurkin, Alexander V.,Yurovskaya, Marina A.
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p. 10125 - 10134
(2013/01/15)
-
- Efficient catalytic transition-metal-free conditions for nucleophilic addition of arylacetylenes to aromatic ketones
-
A mild, efficient, and transition-metal-free method for nucleophilic addition of arylacetylenes to diverse aromatic ketones, using catalytic amount of tetrabutylammonium chloride as a promoter and solid KOH as a base in THF, was developed to afford aromat
- Liu, Junfeng,Lin, Jin,Song, Ling
-
supporting information; experimental part
p. 2160 - 2163
(2012/05/05)
-
- Regioselectivity switch: Gold(I)-catalyzed oxidative rearrangement of propargyl alcohols to 1,3-diketones
-
The gold(I)-catalyzed oxidative rearrangement of propargyl alcohols provides an efficient and selective route to 1,3-diketones under mild conditions. Pyridine-N-oxides were used as external oxidants with, different from related substrates, no alkylidenecycloalkanones or oxetan-3-ones formed as side-products.
- Hashmi, A. Stephen K.,Wang, Tao,Shi, Shuai,Rudolph, Matthias
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p. 7761 - 7767
(2012/11/07)
-
- Synthesis of 2-phenyl-4,5,6,7-tetrahydro-1H-indoles with a chiral substituent at the nitrogen atom
-
An efficient method has been developed for the enantioselective synthesis of 2-phenyl-4,5,6,7-tetra-hydro-1H-indoles containing chiral substituents at the nitrogen atom. It is based on opening of the epoxide fragment of 1-phenylethynyl-7-oxabicyclo[4.1.0]
- Andreev, I. A.,Ryzhkov, I. O.,Kurkin, A. V.,Yurovskaya, M. A.
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p. 715 - 719,5
(2020/09/09)
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- Silver-catalyzed direct addition of terminal alkynes to simple cyclic ketones in water
-
The first catalytic addition of terminal alkynes to simple cyclic ketones in water catalyzed by silver was developed. Cyclic ketones were reacted with terminal alkynes efficiently in water to give the corresponding propargyl alcohols. Georg Thieme Verlag
- Jia, Zhenhua,Li, Xingshu,Chan, Alberts. C.,Li, Chao-Jun
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p. 2758 - 2762
(2013/02/21)
-
- Heteropolyacid-catalyzed direct deoxygenation of propargyl and allyl alcohols
-
The combination of H3[PW12O40] ?nH2O (1 mol %) and Et3SiH led to the direct catalytic deoxygenation of propargyl alcohols, in which proper solvent selection Cl(CH2)2Cl vs CF3CH2OH was the key to obtaining better product yields. Under similar conditions, the deoxygenation of allyl alcohols proceeded to give thermodynamically stable alkenes with migration of the double bonds in good yields.
- Egi, Masahiro,Kawai, Takuya,Umemura, Megumi,Akai, Shuji
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experimental part
p. 7092 - 7097
(2012/10/07)
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- Gold-catalyzed isomerization of unactivated allenes into 1,3-dienes under ambient conditions
-
We have developed a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.
- Ting, Chun-Ming,Hsu, Yi-Ling,Liu, Rai-Shung
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supporting information; experimental part
p. 6577 - 6579
(2012/07/31)
-
- Copper-catalyzed, aerobic oxidative cross-coupling of alkynes with arylboronic acids: Remarkable selectivity in 2,6-lutidine media
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Aerobic oxidative cross-coupling reactions between alkynes and boronic acids under mild conditions catalyzed by low loadings of a copper salt are reported. 2,6-Lutidine accelerated the reactions dramatically, and the desired coupling products were obtained in high yields with high selectivities.
- Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Sh
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supporting information; experimental part
p. 6208 - 6210
(2011/10/10)
-
- Exploratory studies on the reaction between iodoarenes and acetylenes: One-pot, Pd-[Bmim][BF4] catalyzed preparation of trianisylethylene
-
The reaction between iodoarenes and acetylenes mediated by palladium was studied, showing selectivity changes based on the nature of the substituent. A new, phosphine-, copper-, and amine-free methodology was developed, in which the synthesis of trianisylethylene from 4-iodoanisole and trimethylsilylacetylene was promoted presumably by an N-heterocyclic-carbene derived from an ionic liquid and a palladium salt, using ethanol as the hydrogen source. Graphical Abstract: [Figure not available: see fulltext.]
- Barros, Jose C.,Souza, Andrea L. F.,Da Silva, Joaquim F. M.,Antunes
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scheme or table
p. 549 - 553
(2012/01/13)
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- Palladium-catalyzed coupling of propargylic carbonates with N-tosylhydrazones: Highly selective synthesis of substituted propargylic N-sulfonylhydrazones and vinylallenes
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An efficient palladium-catalyzed coupling of propargylic carbonates (1) with N-tosylhydrazones (2, 2′) has been carried out. A wide range of propargylic N-sulfonylhydrazones (3) and multisubstituted vinylallenes (4) can be obtained selectively by using either [PdCl2(CH3CN) 2] or [Pd2(dba)3] as catalysts. (dba=trans,trans-dibenzylideneacetone, dppp=propane-l,3- diylbis(diphenylphosphane), Ts=4-toluenesulfonyl.) Copyright
- Chen, Zi-Sheng,Duan, Xin-Hua,Wu, Lu-Yong,Ali, Shaukat,Ji, Ke-Gong,Zhou, Ping-Xin,Liu, Xue-Yuan,Liang, Yong-Min
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p. 6918 - 6921
(2011/07/08)
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- Transition-metal-free alkynylation of aryl chlorides
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Two sets of conditions have been developed for a base-mediated, transition-metal-free alkynylation of aryl chlorides that proceeds via benzyne intermediates. The first set of conditions involves the use of TMPLi base in a pentane/THF mixture at 25 °C. The
- Truong, Thanh,Daugulis, Olafs
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supporting information; experimental part
p. 4172 - 4175
(2011/10/02)
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- Synthesis of phosphine-ligated zinc acetylide dimers: Enhanced reactivity in carbonyl additions
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Phosphine-ligated dinuclear zinc acetylides effectively promote the alkynylation of carbonyl derivatives. Good to excellent yields (46-91%) of the corresponding propargylic alcohols were obtained from a wide range of substrates. Crystallographic evidence
- Wilson, Erin E.,Oliver, Allen G.,Hughes, Russell P.,Ashfeld, Brandon L.
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experimental part
p. 5214 - 5221
(2011/11/13)
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- Palladium-catalyzed intramolecular hydroarylation of 2-bromobenzyl propargyl ethers: A new access to exocyclic isochromans
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An efficient, stereo- and regioselective palladium-catalyzed 6-exo-dig intramolecular hydroarylation of propargyl ethers which provides a concise access to functionalized isochromans in high yields has been developed. A wide range of substrates possessing aromatic, aliphatic and heteroaromatic alkynes can be efficiently transformed into the targeted isochromans. Irrespective of the nature of the substrates, the cyclization follows highly selective -stereo- and regiochemistry.
- Nandakumar, Avanashiappan,Balakrishnan, Krishnamoorthy,Perumal, Paramasivan Thirumalai
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scheme or table
p. 2733 - 2739
(2011/12/04)
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- Domino gold-catalyzed rearrangement and fluorination of propargyl acetates
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A combination of IPrAuNTf2 as catalyst in the presence of Selectfluor has been successfully used for the high yielding synthesis of α-fluoroenones via 1,3-acyloxy rearrangement of propargyl acetates followed by Csp2-F bond formation,
- De Haro, Teresa,Nevado, Cristina
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supporting information; experimental part
p. 248 - 249
(2011/02/23)
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- Electrophilic carbocyclization of aryl propargylic alcohols: A facile synthesis of diiodinated carbocycles and heterocycles
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Diiodinated carbocycles and oxygen heterocycles can be readily synthesized by electrophilic carbocyclization of aryl propargylic alcohols in moderate to good yields under mild conditions. The resulting diiodide can be further exploited by subsequent oxidi
- Zhu, Hai-Tao,Ji, Ke-Gong,Yang, Fang,Wang, Li-Jing,Zhao, Shu-Chun,Ali, Shaukat,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information; experimental part
p. 684 - 687
(2011/05/03)
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- Highly efficient copper-catalyzed synthesis of internal alkynes via aerobic oxidative arylation of terminal alkynes
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We have developed a novel and highly efficient, copper-catalyzed synthesis of internal alkynes via oxidative couplings of aromatic boronic acids with terminal alkynes at room temperature. The protocol uses inexpensive copper(I) oxide [Cu2O] as the catalyst, oxygen in the air as the stoichiometric oxidant; no ligand and sealed reaction vessels are required, and remarkable functional group tolerability is observed with coupling occurring.
- Rao, Honghua,Fu, Hua,Jiang, Yuyang,Zhao, Yufen
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supporting information; experimental part
p. 458 - 462
(2010/05/19)
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- Double dehydro-diels-alder reactions of 1,5-dien-3-ynes
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A study was conducted to demonstrate double dehydro-diels-alder reactions of 1,5-dien-3-ynes. It was demonstrated that the reaction proceeded through two concerted cycloadditions, the first of which was proposed to be reversible. Detailed analysis reveale
- Fallon, Thomas,Robinson, Diane E.J.E.,Willis, Anthony C.,Paddon-Row, Michael N.,Sherburn, Michael S.
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supporting information; experimental part
p. 760 - 765
(2010/05/18)
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- Palladium-catalyzed cross-coupling reaction of aryl trimethoxysilanes with terminal alkynes
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A palladium-catalyzed cross-coupling reaction of aryl trimethoxysilanes with terminal alkynes was described. Thus, di-substituted alkynes were prepared in moderate to good yields. The electron-deficient terminal alkynes also worked well in the procedure.
- Ye, Zhishi,Liu, Miaochang,Lin, Baoda,Wu, Huayue,Ding, Jinchang,Cheng, Jiang
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scheme or table
p. 530 - 532
(2009/04/14)
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- Copper- and phosphine-free Sonogashira coupling reaction catalyzed by polyurea-encapsulated palladium(II)
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A polyurea-encapsulated palladium catalyst (Pd EnCat 30) was first applied to Sonogashira cross-coupling reactions in the absence of a copper salt co-catalyst and under phosphine-free conditions. This polymer-anchored homogeneous palladium catalyst effici
- Kuang, Yun-Yan,Chen, Fen-Er
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experimental part
p. 897 - 902
(2009/08/14)
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- Gold-catalyzed efficient preparation of linear α-haloenones from propargylic acetates
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Versatile linear α-iodo- and α-bromoenones are prepared efficiently from readily accessible propargylic acetates using 2 mol % of Au(PPh3)NTf2. This reaction is easy to execute and has broad substrate scope. Good to excellent Z-selectivities are observed in the cases of propargylic acetates derived from aliphatic aldehydes.
- Yu, Meng,Zhang, Guozhu,Zhang, Liming
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experimental part
p. 1846 - 1855
(2009/07/04)
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