- Electrochemical oxidation-induced benzyl C–H carbonylation for the synthesis of aromatic α-diketones
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Electrochemical oxidation-induced direct carbonylation of benzyl C–H bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in the air is used as an oxygen source.
- Tan, Yu-Fang,Chen, Yuan,Li, Rui-Xue,Guan, Zhi,He, Yan-Hong
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supporting information
(2021/12/21)
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- Synthesis ofN-alkoxyphthalimide derivativesviaPIDA-promoted cross dehydrogenative coupling reaction
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A PIDA-promoted cross-dehydrogenative coupling reaction betweenN-hydroxyphthalimide (NHPI) and aryl ketones for efficient synthesis ofN-alkoxyphthalimide products in moderate to good yields has been described. This methodology is distinguished by catalyst-free conditions, readily available starting materials, wide substrate scope and operational simplicity. In addition, a gram-scale reaction and synthetic transformation of the product into synthetically useful intermediates has been demonstrated.
- Chen, Rongxiang,Liu, Bing,Li, Wenbo,Wang, Kai-Kai,Miao, Changqing,Li, Zhizhuang,Lv, Yingjie,Liu, Lantao
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p. 8051 - 8054
(2021/03/03)
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- Iron-Promoted Domino Dehydrogenative Annulation of Deoxybenzoins and Alkynes Leading to β-Aryl-α-Naphthols
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A strategy for synthesis of β-aryl-α-naphthols has been established through an iron-promoted domino C(sp3)?H/C(sp)?H and C(sp2)?H/C(sp)?H dehydrogenative coupling of deoxybenzoins and alkynes. The synthesis uses inexpensive materials
- Zhu, Xue-Qing,Guo, Rui-Li,Zhang, Xing-Long,Gao, Ya-Ru,Jia, Qiong,Wang, Yong-Qiang
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supporting information
p. 3190 - 3201
(2020/07/13)
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- Iodine/DMSO promoted oxidation of benzylic Csp3–H bonds to diketones – A mechanistic investigation
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This article describes a mechanistic investigation into the I2/DMSO mediated benzylic Csp3–H oxidation of an α-methylene ketone. The electron paramagnetic resonance (EPR) spectrum centred at g = 2.0011 supports the involvement of iodine and benzylic radicals, as the α-iodinated compound 2-iodo-1,2-diphenylethanone was isolated as a key reactive intermediate. The oxidation reaction relies, primarily, on DMSO as a source of oxygen in benzil, proven by the reaction of benzyl phenyl ketone with diphenyl sulfoxide (DPSO).
- Jayram, Janeeka,Xulu, Bheki A.,Jeena, Vineet
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- An iodine/DMSO-catalyzed sequential one-pot approach to 2,4,5-trisubstituted-1H-imidazoles from α-methylene ketones
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A sequential one-pot approach to 2,4,5-trisubstituted imidazoles has been developed from α-methylene ketones and aldehydes. This methodology employs air-moisture stable reaction conditions and an inexpensive iodine/DMSO system affording a diverse range of known and novel (substrate scope) 2,4,5-trisubstituted imidazoles in moderate to excellent yields. The iodine/DMSO system was extended to the domino convergent synthesis of two functionalized intermediates, benzil and benzaldehyde, to produce the final product.
- Jayram, Janeeka,Jeena, Vineet
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p. 37557 - 37563
(2018/11/26)
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- Silver-Catalyzed Coupling of Two Csp3-H Groups and One-Pot Synthesis of Tetrasubstituted Furans, Thiophenes, and Pyrroles
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Silver-catalyzed coupling of two Csp3-H groups to form 1,4-diketones have been developed for the first time. The resultant ketones then undergo cyclization to synthesize tetrasubstituted furans, thiophenes, and pyrroles from benzyl ketone derivatives in a one-pot reaction process. This highly-efficient synthetic method, which utilizes air as the terminal oxidant and readily accessible starting materials, displays a wide substrate scope and broad functional-group tolerance.
- Mao, Shuai,Zhu, Xue-Qing,Gao, Ya-Ru,Guo, Dong-Dong,Wang, Yong-Qiang
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supporting information
p. 11335 - 11339
(2015/08/03)
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- Copper-catalyzed base-accelerated direct oxidation of C-H bond to synthesize benzils, isatins, and quinoxalines with molecular oxygen as terminal oxidant
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We describe herein an efficient and general copper (II)-catalyzed base-accelerated oxidation of the C-H bond to synthesize benzils and isatins. With similar oxidation system an efficient one-pot procedure for the synthesis of quinoxaline derivatives was realized. The two protocols feature using molecular oxygen as terminal oxidant, low catalyst loading, wide substrate scope, and high functional-group tolerance.
- Yu, Jing-Wen,Mao, Shuai,Wang, Yong-Qiang
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p. 1575 - 1580
(2015/03/14)
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- Facile and highly diastereoselective synthesis of syn- and cis-1,2-diol derivatives from protected α-hydroxy ketones
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An efficient method for the synthesis of monoprotected syn- or cis-1,2-diol derivatives by reduction of easily accessible α-(2,2,6,6-tetramethylpiperidinyloxy) ketones is reported. The α-(tetramethylpiperidinyloxy) group as the stereodirecting group induces in unhindered acyclic or cyclic ketones complete syn- or cis-diastereoselectivity, respectively, with L-Selectride. For more hindered derivatives, where L-Selectride becomes unreactive, LiAlH4 proved effective, essentially showing the same high selectivity. The diastereoselectivity of the reduction can be rationalized for acyclic ketones by the Felkin-Anh model, whereas for cyclic substrates, attack from the face opposite to the tetramethylpiperidinyloxy group predictably prevails with high selectivity regardless of the substitution pattern. The liberation of free diols was achieved by reductive N-O bond cleavage of the alkoxyamine unit. Monoprotected syn- and cis-1,2-diols were synthesized by reduction of ketones bearing the stereodirecting α-(2,2,6,6-tetramethylpiperidinyloxy) group. The latter induces syn- or cis-selectivity in unhindered acyclic or cyclic ketones with L-Selectride, whereas the smaller LiAlH4 induced excellent diastereoselectivity with hindered ketones. Free 1,2-diols were liberated by reductive N-O bond cleavage.
- Jahn, Emanuela,Smr?ek, Jakub,Pohl, Radek,Císa?ová, Ivana,Jones, Peter G.,Jahn, Ullrich
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supporting information
p. 7785 - 7798
(2015/12/31)
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- Copper(II)-promoted C-C bond formation by oxidative coupling of two C(sp3)-H bonds adjacent to carbonyl group to construct 1,4-diketones and tetrasubstituted furans
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The copper(II)-promoted C-C bond formation from the coupling of two C(sp3)-H bonds that are adjacent to a carbonyl group was achieved. This protocol offers a simple and efficient approach to 2,3-disubstituted 1,4-diketones and tetrasubstituted furans. This method features a wide substrate scope and high functional group tolerance.
- Mao, Shuai,Gao, Ya-Ru,Zhang, Shao-Liang,Guo, Dong-Dong,Wang, Yong-Qiang
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p. 876 - 885
(2015/01/30)
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- Aerobic dehydrogenative α-diarylation of benzyl ketones with aromatics through carbon-carbon bond cleavage
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Substituted benzyl ketones reacted with aromatics in the presence of K 2S2O8 in CF3COOH at room temperature, yielding α-diaryl benzyl ketones through a carbon-carbon bond cleavage. In the reaction, two new carbon-carbon bonds were formed and one carbon-carbon bond was cleaved. It is very interesting that two different nucleophiles such as benzyl ketones and aromatics were coupled together without metal, which is unusual in organic synthesis.
- More, Nagnath Yadav,Jeganmohan, Masilamani
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supporting information
p. 804 - 807
(2014/03/21)
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- Alkyne-functional homopolymers and block copolymers through nitroxide-mediated free radical polymerization of 4-(phenylethynyl)styrene
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Nitroxide-mediated polymerization of the alkyne-functional monomer 4-(phenylethynyl)-styrene allows the preparation of homopolymers and block copolymers with narrow molecular weight distributions. At higher conversions, side reactions, including addition
- Sessions, Laura B.,Miinea, Liliana A.,Ericson, Kjell D.,Glueck, David S.,Grubbs, Robert B.
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p. 2116 - 2121
(2007/10/03)
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- The thermolysis and photochemistry of hybrid initiators for 'living' free radical polymerization
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A new initiator potentially capable of both thermal and photochemical initiation of 'living' free radical polymerization (LFRP) has been prepared. Both of these reaction pathways have been examined and identified in terms of their products. The thermal reaction is highly dependent on the reaction conditions and displays competitive radical and ionic reactivity. In the presence of a proton source, the ionic pathway is highly favored. Photochemical activation leads predominantly to Norrish type I cleavage where the photoproducts further react by α-cleavage resulting in the formation of benzaldehyde.
- Skene,Connolly, Terrence J.,Scaiano
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p. 7297 - 7302
(2007/10/03)
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