- Synthesis of Highly Substituted Biaryls by the Construction of a Benzene Ring via in Situ Formed Acetals
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Herein, we present an interesting method for the construction of a benzene ring using propargylic alcohols and 1,3-dicarbonyls, which involves three new C-C bond formations via cascade alkylation, formylation, annulation, and aromatization to make substituted biaryls. This one-pot Br?nsted acid-promoted protocol utilizes the unique reactivity of the acetal formed under the reaction conditions. Alkynyl methyl ketones could be employed instead of 1,3-dicarbonyls as they are converted to 1,3-dicarbonyls by hydration under the reaction conditions.
- Balamurugan, Rengarajan,Manojveer, Seetharaman,Tarigopula, Chandrahas
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p. 11871 - 11883
(2021/09/13)
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- Silver Mediated Banert Cascade with Carbon Nucleophiles
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The Banert cascade of propargylic azides can be promoted by simple silver salts, and the triazafulvene intermediate can be intercepted by carbon nucleophiles. Various indoles (>25 examples, up to 92% yield) and electron-rich heterocycles were effective. T
- Alexander, Juliana R.,Kevorkian, Paul V.,Topczewski, Joseph J.
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supporting information
p. 3227 - 3230
(2021/05/05)
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- Intercepting the Banert cascade with nucleophilic fluorine: Direct access to α-fluorinated: N H-1,2,3-triazoles
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The treatment of propargylic azides with silver(i) fluoride in acetonitrile was found to yield α-fluorinated NH-1,2,3-triazoles via the Banert cascade. The reaction was regioselective and the products result from an initial [3,3] rearrangement. The reacti
- Alexander,Kevorkian,Topczewski
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supporting information
p. 5024 - 5027
(2021/05/28)
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- Kinetic Resolution of Propargylic Ethers via [2,3]-Wittig Rearrangement to Synthesize Chiral α-Hydroxyallenes
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An efficient kinetic resolution of propargyloxy dicarbonyl compounds via asymmetric [2,3]-Wittig rearrangement was achieved by using a chiral N,N′-dioxide/NiII complex catalyst. Various chiral α-allenyl alcohols were obtained in high enantioselectivities under mild conditions. The utility of this method was readily demonstrated in the asymmetric synthesis of the chiral 2,5-dihydrofuran derivative.
- Xu, Xi,Dong, Shunxi,Feng, Lili,Wang, Sijing,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 2692 - 2696
(2020/03/30)
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- Divergent Mechanisms of the Banert Cascade with Propargyl Azides
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Triazoles are privileged heterocycles for a variety of applications. The synthesis of 1H-triazoles can be accomplished by the Banert cascade from propargylic azides. Depending on the substrate and conditions, the Banert cascade can proceed by either a sigmatropic or prototropic mechanism. This report describes the first detailed kinetic analysis of the Banert cascade proceeding by both pathways including substituent effects and KIE. The analysis identified the inflection point in the divergent pathways, allowing future work to predict which Banert products are accessible.
- Alexander, Juliana R.,Packard, Mary H.,Hildebrandt, Alanna M.,Ott, Amy A.,Topczewski, Joseph J.
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p. 3174 - 3181
(2020/03/23)
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- Synthesis of substituted benzo[: B] [1,4]oxazepine derivatives by the reaction of 2-aminophenols with alkynones
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We have developed a novel synthetic method accessing benzo[b][1,4]oxazepines that are one of the rare classes of benzoxazepine derivatives by reaction of 2-aminophenols with alkynones in 1,4-dioxane at 100 °C. A series of benzo[b][1,4]oxazepine derivatives can be prepared by using this synthetic protocol. Mechanistic experiments indicated that the hydroxy proton of the aminophenol could play a crucial role in the formation of an alkynylketimine intermediate that undergoes 7-endo-dig cyclization.
- Oshimoto, Kohei,Zhou, Biao,Tsuji, Hiroaki,Kawatsura, Motoi
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supporting information
p. 415 - 419
(2020/01/30)
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- Transition-Metal-Free Synthesis of Electron Rich 1,3-Dienes via Base Promoted Isomerization of Propargylic Ethers
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Herein, a novel and scalable synthesis of electron rich 1,3-dienes based on KOtBu mediated isomerization of propargylic ether derivatives was developed. This new process features easy handling reaction conditions, transition-metal-free isomerization, high isolated yields, and most of all, it could be used for modification of natural products at late stage functionalizations.
- Liu, Chunxiang,Deng, Guogang,Li, Xin,Xu, Yiren,Yu, Kaili,Chen, Wen,Zhang, Hongbin,Yang, Xiaodong
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supporting information
p. 483 - 487
(2020/01/25)
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- Nickel-Catalyzed Directed Hydroarylation of Alkynes with Boronic Acids
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A regio- and stereoselective nickel-catalyzed hydroarylation of alkynes using propargylic carbamates as directing groups has been developed. The reaction proceeds under mild reaction conditions using arylboronic acids in the absence of base. A range of heterocycles and functional groups are tolerated under the reaction conditions, providing high yields of trisubstituted alkenes with control of olefin geometry.
- Hanna, Luke E.,Konev, Mikhail O.,Jarvo, Elizabeth R.
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supporting information
p. 184 - 187
(2018/12/05)
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- Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: Synthesis of propargyl alcohols and α-ketoesters
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The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere (N2 or O2). A N2 atmosphere favours propargyl alcohols via a direct C-C coupling process, whereas an O2 atmosphere results in the generation of α-ketoesters through the oxidative CC/C-O coupling pathway.
- Ni, Ke,Meng, Ling-Guo,Ruan, Hongjie,Wang, Lei
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supporting information
p. 8438 - 8441
(2019/07/22)
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- Phosphine-Catalyzed Intermolecular Annulations of Fluorinated ortho-Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition
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A phosphine-catalyzed intermolecular annulation reaction of functionalized ortho-aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2-alkynylquinolines and benzo-fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. (Figure presented.).
- Zhang, Yanshun,Sun, Yaoliang,Wei, Yin,Shi, Min
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supporting information
p. 2129 - 2135
(2019/03/13)
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- Enantioselective Cyanosilylation of Alkynyl Ketones Catalyzed by Combined Systems Consisting of Chiral Ruthenium(II) Complex and Lithium Phenoxide
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Asymmetric cyanosilylation of alkynyl ketones with the catalyst systems consisting of amino acid/2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP)/ruthenium(II) complex and lithium phenoxide (Ru?Li cat.) was studied. The reaction was conducted in tert-butyl methyl ether (TBME) at ?78 °C with a substrate-to-catalyst molar ratio (S/C) as high as 2000. A series of simple and functionalized ketones was converted into the alkynyl tertiary cyanohydrin derivatives in up to 99% ee. Appropriate selection of an amino-acid ligand of the catalyst according to the substrate structure was crucially important to achieve high enantioselectivity and a wide scope of substrates. Transformation of the chiral cyanohydrin product into a functionalized lactone was also examined. (Figure presented.).
- Ohkuma, Takeshi,Kurono, Nobuhito,Sakaguchi, Yusuke,Yamauchi, Kohei,Yurino, Taiga
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supporting information
p. 1517 - 1522
(2018/02/28)
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- NiICatalyzes the Regioselective Cross-Coupling of Alkylzinc Halides and Propargyl Bromides to Allenes
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We describe the unprecedented formation of allenes by Ni-catalyzed cross-coupling of propargyl bromides with alkylzinc halides. The reaction regioselectivity is complementary to the previously reported formation of propargyl-coupled compounds. Experiments
- Soler-Yanes, Rita,Arribas-álvarez, Iván,Guisán-Ceinos, Manuel,Bu?uel, Elena,Cárdenas, Diego J.
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supporting information
p. 1584 - 1590
(2017/02/10)
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- Gold-catalyzed Fluorination of Alkynyl Esters and Ketones: Efficient Access to Fluorinated 1,3-Dicarbonyl Compounds
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We developed an efficient synthesis of 2-fluoro-1,3-dicarbonyl compounds using readily available alkynyl ketones or esters as starting material. The key step is the insertion of hydrogen fluoride (HF) to the gold carbene intermediate generated from cationic gold catalyzed addition of N-oxides to alkynyl ketones or esters. This method gives excellent chemical yields and regioselectivity with good functional group tolerance. (Figure presented.).
- Zeng, Xiaojun,Lu, Zhichao,Liu, Shiwen,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 4062 - 4066
(2017/11/30)
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- Lewis base-catalyzed reactions of cyclopropenones: Novel synthesis of mono- or multi-substituted allenic esters
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The reactions of cyclopropenones with nucleophiles (H2O or methanol) could be catalyzed by nitrogen-containing Lewis bases or phosphorus-containing Lewis bases, affording the corresponding mono- or multi-substituted allenic esters in moderate t
- Yang, Yuan-Liang,Zhang, Zhen,Zhang, Xiao-Nan,Wang, De,Wei, Yin,Shi, Min
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supporting information
p. 115 - 117
(2014/01/06)
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- Synthesis of highly substituted allylic alcohols by a regio- and stereo-defined CuCl-mediated carbometallation reaction of 3-aryl-substituted secondary propargylic alcohols with Grignard reagents
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A highly regio- and stereoselective CuCl-mediated carbometallation reaction of 3-aryl-substituted secondary propargylic alcohols with alkyl, aryl, vinyl or allyl Grignard reagents for the synthesis of fully-substituted allylic alcohols was developed. The R2 group from the Grignard reagent was successfully introduced to the 2-position of the propargylic alcohols due to the chelation of metal atom with the hydroxyl oxygen atom forming 5-membered metallacyclic intermediates, which smoothly react with various electrophiles to afford stereodefined polysubstituted allylic alcohols. By this method, optically active allylic alcohols can be prepared from readily available optically active propargylic alcohols without obvious racemization. Five-membered lactones can also be synthesized by Pd-catalyzed carbonylation with iodoallylic alcohols. The Royal Society of Chemistry 2009.
- Zhang, Xiaobing,Lu, Zhan,Fu, Chunling,Ma, Shengming
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supporting information; experimental part
p. 3258 - 3263
(2009/10/24)
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- Cannabinoid receptor modulators
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A compound having the general structure of Formula (I): or a pharmaceutically acceptable salt, solvate, or ester thereof, is useful in treating diseases, disorders, or conditions such as obesity, metabolic disorders, addiction, diseases of the central nervous system, cardiovascular disorders, respiratory disorders, and gastrointestinal disorders.
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Page/Page column 138-139
(2010/11/28)
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- Enantioselective synthesis of both enantiomers of various propargylic alcohols by use of two oxidoreductases
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The oxidoreductases Lactobacillus brevis alcohol dehydrogenase (LBADH) and Candida parapsilosis carbonyl reductase (CPCR) are suitable catalysts for the reduction of ketones to afford enantiopure sec. alcohols. A broad variety of alkynones (1, 3, and 5) are accepted as substrates and the corresponding propargylic alcohols (2, 4, and 6) are obtained in good yield and excellent enantiomeric excess. By changing the steric demand of the substituents the ee values can be adjusted and even the configurations of the products can be altered.
- Schubert, Thomas,Hummel, Werner,Kula, Maria-Regina,Mueller, Michael
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p. 4181 - 4187
(2007/10/03)
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- Psychoactive propargylamine derivatives used in the treatment of anxiety, psychotic states or aggression
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Propargylamine derivatives having the general formula: STR1 wherein R is a hydrogen atom, an unsubstituted phenyl group or a phenyl group substituted with halogen, trifluoromethyl, loweralkoxy, nitro, cyano, amido or N,N-diloweralkylamido, R1,
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