- Copper-catalyzed asymmetric cyanation of alkenes via carbonyl-assisted coupling of alkyl-substituted carbon-centered radicals
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Based on a copper-catalyzed radical relay strategy, the first copper-catalyzed asymmetric cyanation of alkyl-substituted alkenes has been developed. The reaction, featuring mild reaction conditions and excellent functional group compatibilities, provides
- Zhou, Song,Zhang, Guoyu,Fu, Liang,Chen, Pinhong,Li, Yibiao,Liu, Guosheng
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- Rapid and solvent-free synthesis of homoallyl or homopropargyl alcohols mediated by zinc powder
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A rapid and efficient procedure for the solvent-free synthesis of homoallylic and homopropargyl alcohols has been achieved by zinc-mediated Barbier-type reaction of carbonyl compounds at room temperature. Georg Thieme Verlag Stuttgart.
- Wang, Jin-Xian,Jia, Xuefeng,Meng, Tuanjie,Xin, Li
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- Mg(NTf2)2xH22: An efficient catalyst for the synthesis of homoallylic alcohols in water
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An efficient method has been developed for the allylation of aldehydes with allytributylstannane in the presence of a catalytic amount of Mg(NTf 2)2xH22 at room temperature in water to afford the corresponding homoallylic
- Wang, Hong-She,Zeng, Jun-E
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- Catalytic Photoredox Allylation of Aldehydes Promoted by a Cobalt Complex
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The preparation of homoallylic alcohols by addition of organometallic allyl compounds to carbonyls is an important strategy in organic chemistry. Allylating organometallic cobalt species can be generated employing stoichiometric quantities of Zn acting as reductant. To avoid the employment of stoichiometric amount of Zn, we have developed an allylation reaction of aromatic and aliphatic aldehydes promoted by photoredox catalysis in the presence of a cobalt complex, and we present herein a full account of our research. In the presence of the abundant CoBr2 (10 mol %), 4,4′-di-tert-butyl-2,2′-dipyridyl (dtbbpy, 10 mol %), allyl acetate (3 equiv.), [Ir(dtbbpy)(ppy)2]PF6 (ppy=2-phenylpyridine, 2 mol %), and N,N-diisopropylethylamine (4 equiv.), an allylation of aldehydes is taking place, in moderate to good yields. Substrates scope, limitations, and photophysical investigations of this new process are reported. (Figure presented.).
- Gualandi, Andrea,Rodeghiero, Giacomo,Perciaccante, Rossana,Jansen, Thomas Paul,Moreno-Cabrerizo, Cristina,Foucher, Charles,Marchini, Marianna,Ceroni, Paola,Cozzi, Pier Giorgio
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- Palladium-catalyzed anti-Markovnikov oxidative acetalization of activated olefins with iron(iii) sulphate as the reoxidant
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This paper discloses the efficient palladium-catalyzed anti-Markovnikov oxidative acetalization of activated terminal olefins with iron(iii) sulfate as the reoxidant. This methodology requires mild reaction conditions and shows high regioselectivity toward anti-Markovnikov products and compatibility with a wide range of functional groups. Iron(iii) sulphate was the sole reoxidant used in this method. Various olefins like vinylarenes, aryl-allylethers, aryl or benzyl acrylates and homoallylic alcohols all reacted well providing anti-Markovnikov acetals, some of which represent orthogonally functionalized 1,3- and 1,4-dioxygenated compounds.
- Fernandes, Rodney A.,Kumar, Praveen,Yadav, Sandhya S.
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p. 427 - 443
(2022/01/20)
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- Organocatalytic Asymmetric Synthesis of Cyclic Acetals with Spirooxindole Skeleton
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An organocatalytic asymmetric synthesis of cyclic acetal with spirooxindole skeleton has been developed via a domino reaction between isatin and γ-hydroxy enones. Bifunctional squaramide catalyst with adamantyl motif was found to be the most effective for the cascade reaction. With 10 mol% of the catalyst, the desired products were obtained in 1.8:1 to 9:1 diastereo- and 86% to >99% enantioselectivities from a range of substituted isatins and γ-hydroxy enones. (Figure presented.).
- Shikari, Amit,Mandal, Koushik,Chopra, Deepak,Pan, Subhas Chandra
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supporting information
p. 58 - 63
(2021/11/09)
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- Photoredox Allylation Reactions Mediated by Bismuth in Aqueous Conditions
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Organometallic allylic reagents are widely used in the construction of C?C bonds by Barbier-type reactions. In this communication, we have described a photoredox Barbier allylation of aldehydes mediated by bismuth, in absence of other metals as co-reductants. Mild reaction conditions, tolerance of oxygen, and use of aqueous solvent make this photoredox methodology attractive for green and sustainable synthesis of homoallylic alcohols.
- Potenti, Simone,Gualandi, Andrea,Puggioli, Alessio,Fermi, Andrea,Bergamini, Giacomo,Cozzi, Pier Giorgio
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supporting information
p. 1624 - 1627
(2021/02/05)
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- Ni-Catalyzed 1,2-Diarylation of Alkenyl Ketones: A Comparative Study of Carbonyl-Directed Reaction Systems
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A nickel-catalyzed 1,2-diarylation of alkenyl ketones with aryl iodides and arylboronic esters is reported. Ketones with a variety of substituents serve as effective directing groups, offering high levels of regiocontrol. A representative product is diversified into a wide range of useful products that are not readily accessible via existing 1,2-diarylation reactions. Preliminary mechanistic studies shed light on the binding mode of the substrate, and Hammett analysis reveals the effect of electronic factors on initial rates.
- Apolinar, Omar,Derosa, Joseph,Engle, Keary M.,Karunananda, Malkanthi K.,Kleinmans, Roman,Li, Zi-Qi,Tran, Van T.,Wisniewski, Steven R.
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supporting information
p. 5311 - 5316
(2021/07/26)
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- Photoinduced Olefin Diamination with Alkylamines
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Vicinal diamines are ubiquitous materials in organic and medicinal chemistry. The direct coupling of olefins and amines would be an ideal approach to construct these motifs. However, alkene diamination remains a long-standing challenge in organic synthesis, especially when using two different amine components. We report a general strategy for the direct and selective assembly of vicinal 1,2-diamines using readily available olefin and amine building blocks. This mild and straightforward approach involves in situ formation and photoinduced activation of N-chloroamines to give aminium radicals that enable efficient alkene aminochlorination. Owing to the ambiphilic nature of the β-chloroamines produced, conversion into tetra-alkyl aziridinium ions was possible, thus enabling diamination by regioselective ring-opening with primary or secondary amines. This strategy streamlines the preparation of vicinal diamines from multistep sequences to a single chemical transformation.
- Angelini, Lucrezia,Govaerts, Sebastian,Hampton, Charlotte,Leonori, Daniele,Malet-Sanz, Laia,Ruffoni, Alessandro
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supporting information
p. 15021 - 15028
(2020/06/17)
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- Enantioselective Synthesis of Isoxazolines Enabled by Palladium-Catalyzed Carboetherification of Alkenyl Oximes
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Reported here is a highly efficient Pd/Xiang-Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with u
- Chen, Mingjie,Li, Wenbo,Wang, Lei,Wang, Yuzhuo,Zhang, Junliang,Zhang, Kenan
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supporting information
p. 4421 - 4427
(2020/02/11)
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- Cp2TiCl2-Catalyzed Photoredox Allylation of Aldehydes with Visible Light
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A Barbier-type Cp2TiCl2-mediated (10 mol %) photoredox allylation of aldehydes under irradiation with visible light (blue light-emitting diodes (LEDs), 450 nm) and in the presence of an organic dye (3DPAFIPN, 5 mol %) with allylbromides is described.
- Bergamini, Giacomo,Calogero, Francesco,Cozzi, Pier Giorgio,Fermi, Andrea,Gualandi, Andrea,Guazzi, Simone,Mazzarini, Martino
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p. 3857 - 3863
(2020/03/26)
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- Electrochemical Chalcogenation of β,γ-Unsaturated Amides and Oximes to Corresponding Oxazolines and Isoxazolines
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The current report represents a transition-metal-free synthesis of oxazoline and isoxazoline derivatives by a tandem electro-oxidative chalcogenation-cyclization process. Both C?Se and C?S bond-forming protocols were developed without using any external oxidant and the reaction was performed at room temperature, open to the air. Using this methodology, 29 substituted oxazoline and 16 substituted isoxazoline derivatives were synthesized with up to 91% isolated yield. (Figure presented.).
- Baidya, Mrinmay,De Sarkar, Suman,Mahanty, Kingshuk,Maiti, Debabrata,Mallick, Samrat
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supporting information
(2020/02/04)
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- Allylation of aldehydes by dual photoredox and nickel catalysis
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Here we report the application of dual nickel/photoredox catalysis to the allylation of aliphatic, aromatic and heteroaromatic aldehydes by using commercially available reagents. The process utilizes the combination of a Ni(ii) complex, [Ru(bpy)3]2+ as a photoredox catalyst, and allylacetate under blue LED irradiation, and allows the synthesis of a large variety of homoallylic alcohols.
- Gualandi, Andrea,Rodeghiero, Giacomo,Faraone, Adriana,Patuzzo, Filippo,Marchini, Marianna,Calogero, Francesco,Perciaccante, Rossana,Jansen, Thomas Paul,Ceroni, Paola,Cozzi, Pier Giorgio
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supporting information
p. 6838 - 6841
(2019/06/18)
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- Copper-Promoted 6- endo-trig Cyclization of β,γ-Unsaturated Hydrazones for the Synthesis of 1,6-Dihydropyridazines
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A novel and efficient strategy for the synthesis of 1,6-dihydropyridazines via copper-promoted 6-endo-trig cyclization of readily available β,γ-unsaturated hydrazones have been developed. A series of 1,6-dihydropyridazines have been synthesized by this method with good yields, high functional group tolerance, and remarkable regioselectivity under mild conditions. Importantly, the 1,6-dihydropyridazines can be efficiently converted to biologically important pyridazines in the presence of NaOH.
- Guo, Yong-Qiang,Zhao, Mi-Na,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 3337 - 3340
(2018/06/11)
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- Nucleo-Palladation-Triggering Alkene Functionalization: A Route to γ-Lactones
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An unprecedented strategy for the highly effective synthesis of γ-lactones from homoallylic alcohols was achieved by palladium catalysis in one step. The protocol affords aryl, alkyl, and spiro γ-lactones directly from readily available homoallylic alcohols in good yields with excellent functional group tolerance and high chemoselectivity under mild conditions.
- Zheng, Meifang,Chen, Pengquan,Huang, Liangbin,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 5756 - 5759
(2017/11/10)
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- Organocatalytic Redox Isomerization of Electron-Deficient Allylic Alcohols: Synthesis of 1,4-Ketoaldehydes
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An organocatalytic redox isomerization strategy has been developed for the synthesis of 1,4-ketoaldehydes. DABCO was found to be the best catalyst for the isomerization of -hydroxy enones. With 20 mol % of DABCO as catalyst and DMSO as the solvent high yi
- Mondal, Keshab,Mondal, Buddhadeb,Pan, Subhas Chandra
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p. 4835 - 4840
(2016/07/06)
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- The solvent-free addition reaction of allylzinc bromide and carbony compounds
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The reactivity of organozincs could be enhanced dramatically under solvent-free conditions. Allylzinc bromide can react rapidly with aldehydes and ketones to give homoallylic alcohols in high yields in the absence of a catalyst under sol vent-free conditions in an open atmosphere at room temperature. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.
- Zhang, Yumei,Jia, Xuefeng,Wang, Jin-Xian
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experimental part
p. 2983 - 2986
(2009/11/30)
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- Combined experimental and theoretical mechanistic investigation of the barbier allylation in aqueous media
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(Chemical Equation Presented) The Barbier allylation of a series of para-substituted benzaldehydes with allylbromide in the presence of Zn, In, Sn, Sb, Bi, and Mg was investigated using competition experiments. In all cases, the slope of the Hammett plots
- Dam, Johan Hygum,Fristrup, Peter,Madsen, Robert
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p. 3228 - 3235
(2008/09/20)
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- Palladium-catalyzed allylation of carbonyl compounds with various allylic compounds using In-InCl3 in aqueous media
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Various allylic compounds can be effectively applied to palladium-catalyzed allylation of carbonyl compounds via the formation of π-allylpalladium(II) intermediates and their transmetalation with indium in the presence of indium trichloride in aqueous media.
- Jang, Taeg-Su,Keum, Gyochang,Kang, Soon Bang,Chung, Bong Young,Kim, Youseung
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p. 775 - 779
(2007/10/03)
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- CARBON-CARBON BOND FORMATION WITH METALLIC MANGANESE
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Metallic manganese is found to reduce allylic bromides and achieve the Barbier-type carbonyl addition of allyl unit.
- Hiyama, Tamejiro,Sawahata, Miwa,Obayashi, Michio
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p. 1237 - 1238
(2007/10/02)
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