- Z-Selective Synthesis of α-Sulfanyl Carbonyl Compounds from Internal Alkynes and Thiols via Photoredox Catalysis
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A synthetically useful Z-selective cascade formal thiyl radical addition, 1,3-double bond isomerization, oxygen trapping reaction, can be promoted by Eosin B under visible light, leading to the construction of 2-aryl- and alkylthio enone derivatives in good yields. An accurate study on the reactivity of different thiols and the screening of the reaction conditions, allowed us to extend this reaction to a large number of substrates, showing a good functional groups tolerance while highlighting the limitations of this procedure. Background experiments and mechanistic studies were also. performed to rationalize this cascade process. The usefulness of this methodology was finally demonstrated via the transformation of a series of α-sulfanyl-enone adducts through selected oxidation reactions, stereoselective synthesis of cyclopropyl ketones, indanones, and pyrazole compounds. (Figure presented.).
- Luridiana, Alberto,Frongia, Angelo,Scorciapino, Mariano Andrea,Malloci, Giuliano,Manconi, Barbara,Serrao, Simone,Ricci, Pier Carlo,Secci, Francesco
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supporting information
p. 124 - 131
(2021/10/12)
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- A Simple Nickel Catalyst Enabling an E-Selective Alkyne Semihydrogenation
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Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom-economic reducing agent dihydrogen (H2), only few catalysts for the challenging E-selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E-selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E-alkenes employing H2, which could serve as a general method for synthesis.
- Thiel, Niklas O.,Kaewmee, Benyapa,Tran Ngoc, Trung,Teichert, Johannes F.
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supporting information
p. 1597 - 1603
(2020/02/05)
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- "Anti-Michael addition" of Grignard reagents to sulfonylacetylenes: Synthesis of alkynes
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In this work, the addition of Grignard reagents to arylsulfonylacetylenes, which undergoes an "anti-Michael addition", resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional
- Esteban, Francisco,Boughani, Lazhar,García Ruano, José L.,Fraile, Alberto,Alemán, José
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p. 3901 - 3908
(2017/07/11)
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- Cu-Catalyzed cascades to carbocycles: Union of diaryliodonium salts with alkenes or alkynes exploiting remote carbocations
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Copper-catalyzed cascade reactions between alkenes or alkynes and diaryliodonium salts form carbocyclic products in a single step. Arylation of the unsaturated functional group is proposed to form a carbocation intermediate that facilitates hydride shift pathways to translocate the positive charge to a remote position and enables ring formation via a Friedel-Crafts-type reaction.
- Zhang, Fengzhi,Das, Shoubhik,Walkinshaw, Andrew J.,Casitas, Alicia,Taylor, Michael,Suero, Marcos G.,Gaunt, Matthew J.
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p. 8851 - 8854
(2014/07/08)
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- Cu-catalyzed arylcarbocyclization of alkynes with diaryliodonium salts through C-c bond formation on inert C(sp3)-H bond
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Copper-catalyzed arylcarbocyclization reaction of alkynes was realized with diaryliodonium salts through C-C bond formation on an inert C(sp3)-H bond. This method provides an efficient cyclization of alkyl alkynes to generate carbocycles with good step-economy. Theoretical study revealed an interesting Cu-catalyzed concerted pathway of the C-C bond formation.
- Peng, Jing,Chen, Chao,Chen, Junjie,Su, Xiang,Xi, Chanjuan,Chen, Hui
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supporting information
p. 3776 - 3779
(2014/08/05)
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- Nickel-catalyzed cross-coupling of primary alkyl halides with phenylethynyl- and trimethylsilyethynyllithium reagents
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A highly efficient alkyl-alkynyl coupling system is described which is promoted by a well-defined and moisture-stable pincer complex [NiCl{C 6H3-2,6-(OPPh2)2}] (1). Non-activated alkyl halides could be efficient
- Xu, Guoqiang,Li, Xiaoyan,Sun, Hongjian
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supporting information; experimental part
p. 3011 - 3014
(2011/08/22)
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- Titanocene(ll)-promoted, one-pot, three-component coupling of thioacetals, alkynyl sulfones, and carbonyl compounds: Highly stereoselective formation of ferf-homopropargyl alcohols
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Titanocene alkylidene complexes, generated by desulfurizative titanation of thioacetals with Cp2Ti[P(OEt)3J2, reacted with alkynyl methyl sulfones to produce organotitanium species, which gave tert-homopropargyl alcohols with high diastereoselectivity on treatment with aromatic and α,β-unsaturated ketones.
- Takeda, Takeshi,Ando, Maiko,Sugita, Takenori,Tsubouchi, Akira
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p. 2875 - 2878
(2008/02/07)
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