- Practical synthesis of α,β-Alkynyl ketones by oxidative alkynylation of aldehydes with hypervalent alkynyliodine reagents
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A practical, metal-free carbonyl C(sp2)H oxidative alkynylation of aldehydes with hypervalent alkynyliodine reagents without the use of any catalysts is described for the synthesis of various α,β-alkynyl ketones. Here, two different methods have been developed where limiting reagents or substrates can be switched, and adopted according to the valuableness of aldehyde substrates or hypervalent alkynyliodine reagents. These reactions proceed with a broad substrate scope and high functional-group compatibility.
- Tsuzuki, Saori,Sakamoto, Ryu,Maruoka, Keiji
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- Coupling and carbonylation of iodoaromatics and terminal alkynes or alkynols catalyzed by a dimeric palladium hydroxide
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The palladium(II) complex [(Ph3P)Pd(Ph)(μ-OH)]2 is an effective catalyst for the coupling aud carbonylation of alkynes and iodoarenes to give acetylenic ketones in 63-94% yields. Acetylenic hydroxy ketones were formed using secondary or tertiary alkynols as reactants.
- Delaude,Masdeu,Alper
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- Decatungstate as Direct Hydrogen Atom Transfer Photocatalyst for SOMOphilic Alkynylation
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A versatile approach for the alkynylation of a variety of aliphatic hydrogen donors, including alkanes, is reported. We used tetrabutylammonium decatungstate as photocatalyst to generate organoradicals from C-H/Si-H bonds via hydrogen atom transfer. The l
- Capaldo, Luca,Ravelli, Davide
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p. 2243 - 2247
(2021/04/05)
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- α- and γ-Regiocontrol and Enantiospecificity in the Copper-Catalyzed Substitution Reaction of Propargylic Phosphates with Grignard Reagents
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The regioselectivity (r.s.) and enantiospecificity (e.s.) of the substitution reactions of secondary propargylic alcohol derivatives using reagents derived from ArMgBr and Cu salts were studied. First, the picolinate, 3-methylpicolinate, and diethylphosph
- Kobayashi, Yuichi,Takashima, Yuji,Motoyama, Yuuya,Isogawa, Yukari,Katagiri, Kyosuke,Tsuboi, Atsuki,Ogawa, Narihito
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p. 3779 - 3785
(2021/02/03)
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- Asymmetric transfer hydrogenation of unsaturated ketones; factors influencing 1,4- vs 1,2- regio- and enantioselectivity, and alkene vs alkyne directing effects
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A detailed study has been completed on the asymmetric transfer hydrogenation (ATH) of a series of enones using Ru(II) catalysts. Electron-rich rings adjacent to the C[dbnd]O group reduce the level of C[dbnd]O reduction compared to C[dbnd]C. The ATH reaction can readily discriminate between double and triple bonds adjacent to ketones, reducing the double bond but leaving a triple bond intact in the major product.
- Hall, Thomas H.,Adams, Hannah,Vyas, Vijyesh K.,Michael Chu,Wills, Martin
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- General Synthesis of α-Alkyl Ynones from Morpholine Amides and 1-Copper(I) Alkynes Promoted by Triflic Anhydride
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The first general method for the synthesis of α-alkyl ynones was developed based on the strategy of electrophilic activation of amides. Its distinctive advantages are attributed to the use of air-stable "bare"1-copper(I) alkyne as a mild nucleophile witho
- Weng, Yunxiang,Min, Lin,Zeng, Xiaobao,Shan, Lidong,Wang, Xinyan,Hu, Yuefei
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supporting information
p. 8296 - 8301
(2020/11/03)
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- Visible light-induced co- or cu-catalyzed selenosulfonylation of alkynes: Synthesis of β-(seleno)vinyl sulfones
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A visible light-induced Co- or Cu-catalyzed selenosulfonylation of alkynes for the synthesis of β-(seleno)vinyl sulfones is demonstrated. This method utilizes a low-cost cobalt salt or metal copper as the catalysts. The reaction goes through a photoinduced free radical addition of selenosulfonates to alkynes for the 1,2-selenosulfonylation of alkynes under mild conditions.
- Ji, Shun-Jun,Wang, Shun-Yi,Xu, Pei,Zhang, Rong
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- Highly regioselective gold-catalyzed formal hydration of propargylic: Gem -difluorides
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Herein, we report a highly regioselective gold-catalyzed formal hydration of propargylic gem-difluorides. Not only does this transformation provide access to versatile fluorinated building blocks that were difficult or hardly possible to access beforehand, but it also represents a rare case of a highly regioselective gold-catalyzed hydroalkoxylation of internal alkynes and puts forward the utility of the difluoromethylene unit as a directing group in catalysis.
- Hamel, Jean-Denys,Hayashi, Tatsuru,Cloutier, Mélissa,Savoie, Paul R.,Thibeault, Olivier,Beaudoin, Meggan,Paquin, Jean-Fran?ois
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p. 9830 - 9836
(2017/12/08)
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- Alkynylation of Csp2 (O)–H Bonds Enabled by Photoredox-Mediated Hydrogen-Atom Transfer
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The development of new hydrogen-atom transfer (HAT) strategies within the framework of photoredox catalysis is highly appealing for its power to activate a desired C?H bond in the substrate leading to its selective functionalization. Reported here is the first photoredox-mediated hydrogen-atom transfer method for the efficient synthesis of ynones, ynamides, and ynoates with high regio- and chemoselectivity by direct functionalization of Csp2 (O)?H bonds. The broad synthetic application of this method has been demonstrated by the selective functionalization of C(O)?H bonds within complex molecular scaffolds.
- Mukherjee, Satobhisha,Garza-Sanchez, R. Aleyda,Tlahuext-Aca, Adrian,Glorius, Frank
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p. 14723 - 14726
(2017/10/18)
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- Direct synthesis of pyrazoles from esters using tert-butoxide-assisted C-(C=O) coupling
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This paper describes the direct synthesis of pyrazoles from esters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield β-ketonitrile or α,β-alkynone intermediates, and condensation by hydrazine addition. The method reported allows for easy control of the regioselectivity and structure of substituents at N-1, C-3, C-4 and/or C-5 positions.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Lee, Sang-Gyeong,Yoon, Hyo Jae,Shin, Dong-Soo,Yoon, Yong-Jin
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supporting information
p. 9201 - 9204
(2015/06/08)
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- Synthesis of β-ketonitriles, α,β-alkynones and biscabinols from esters using tert-butoxide-assisted C(=O)-C (i.e., acyl-C) coupling under ambient conditions
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We demonstrated the synthesis of β-ketonitriles, α,β- alkynones, and biscarbinols using tert-butoxide-assisted C(CO)-C (i.e., acyl-C) coupling of esters under ambient conditions. tert-Butoxide-assisted C(CO)-C (i.e., acyl-C) coupling of esters with cyanomethylenes and acetylenes under transition metal-free ambient conditions gives β-ketonitriles, α,β-alkynones and/or aryl bis(phenylethynyl)carbinols in moderate-to-good yields. It is noteworthy that this is a rapid, facile, and efficient process under ambient conditions, and use of cheap and stable starting materials.
- Kim, Bo Ram,Lee, Hyung-Geun,Kang, Seung-Beom,Jung, Kwang-Ju,Sung, Gi Hyeon,Kim, Jeum-Jong,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 10331 - 10336
(2013/11/19)
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- Synthesis and olefination of carbonyl compounds using solid-supported reagents
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The development and application of three new solid-supported reagents for use in the synthesis or olefination of carbonyl compounds are described. The reagents include the Weinreb amide, Mukaiyama's S-2-pyridyl thioate and a Peterson methylenation reagent. As solid-supports p-benzyl alcohol resin, Wang resin and Merrifield resin (1-2% crosslinked polystyrene) have been used. The Royal Society of Chemistry.
- Hansen, Anne-Lene L.,Murray, Anthony,Tanner, David
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p. 4497 - 4505
(2008/09/18)
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- An unexpected equilibrium process associated with a standard approach to ynone synthesis
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A direct comparison between Weinreb amides and morpholine amides was made with regard to their reactions with alkynyllithium reagents to form ynones. While treatment with stoichiometric alkynyllithium generally effects complete reaction in the case of Weinreb amides, incomplete reactions are obtained from the corresponding morpholine amides. This difference is attributed to an unexpected equilibrium process in the latter case, and it is shown that the use of excess alkynyllithium reagent with morpholine amides provides a synthetically useful synthesis of ynones at 0 °C.
- Jackson, Mary M.,Leverett, Carolyn,Toczko, Jennifer F.,Roberts, John C.
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p. 5032 - 5035
(2007/10/03)
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