- Modular access to 1,2-allenyl ketones based on a photoredox-catalysed radical-polar crossover process
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Herein, a new protocol dealing with the preparation of 1,2-allenyl ketones has been successfully developedviathe reactions of enynes with radicals enabled by dual photoredox/copper catalysis. Based on the results of a deuteration experiment and the competition reaction between cyclopropanation and allenation, the mechanism based on a photoredox-neutral-catalysed radical-polar crossover process has been proposed. Synthetic applications of allenes have also been demonstrated.
- Du, Chan,Fang, Jianghua,Fang, Yewen,Lei, Wan,Li, Yan,Liu, Yongjun
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p. 8502 - 8506
(2021/10/20)
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- Visible light-mediated metal-free double bond deuteration of substituted phenylalkenes
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Various bromophenylalkenes were reductively photodebrominated by using 1,3-dimethyl-2-phenyl-1H-benzo-[d]imidazoline (DMBI) and 9,10-dicyanoanthracene. With deuterated DMBI analogs (the most effective was DMBI-d11), satisfactory to excellent isotopic yields were obtained. DMBI-d11 could also be regenerated from the reaction mixtures with a recovery rate of up to 50%. The combination of the photodebromination reaction with conventional methods for bromoalkene synthesis enables sequential monodeuteration of a double bond without the necessity of a metal catalyst. This journal is
- Iakovenko, Roman,Hlavá?, Jan
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p. 440 - 446
(2021/01/28)
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- Synthesis method of Z-type halogenated chalcone compound
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The invention relates to a synthesis method of a Z-type halogenated chalcone compound as shown in formula (III), characterized by comprising: by using a compound shown in formula (I) and a compound shown in formula (II) as reaction raw materials, using IPrAuCl as a catalyst, using AgSbF as an assistant and using 1,2-dichloroethane as a solvent, performing a reaction at the room temperature; andafter ending the reaction, carrying out post treatment on reaction liquid to obtain the Z-type halogenated chalcone compound as shown in formula (III). The synthesis method disclosed by the inventionis simple and short in step, mild in condition, very high in reaction speed, meanwhile, high in yield and good in regioselectivity, and is a green and economic reaction process; (The formulas are shown in the description.).
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Paragraph 0104; 0106; 0107
(2018/12/13)
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- Photo-induced tandem cyclization of 3-iodoflavones with electron rich five-membered heteroarenes
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Vinyl radicals were generated from 3-iodoflavones under a mercury lamp and tandem cyclization reactions occurred with five-membered heteroarenes entailing two consecutive C-C bond formations to synthesize benzo[e]chromeno[2,3-g]indol-13(1H)-one derivatives. The tandem cyclization reactions worked in acetonitrile without any additives such as transition metals, ligands and oxidants, giving rise to a broad variety of novel polycyclic xanthone frameworks in good yield under mild and environmentally friendly reaction conditions.
- Yang, Qian,Wang, Rui,Han, Jie,Li, Chenchen,Wang, Tao,Liang, Yong,Zhang, Zunting
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p. 43206 - 43211
(2017/09/15)
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- Nucleophilic substitution of α-haloenones with phenols
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The α-haloenones undergo cine-substitution upon reaction with phenolic reagents under basic conditions. A convenient method for the synthesis of push-pull aroxyenones was developed based on this reaction.
- Mareev, Alexander V.,Ushakov, Igor A.,Rulev, Alexander Yu.
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p. 1971 - 1974
(2015/03/30)
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- Visible light photoredox catalyzed cascade cyclizations of α-bromochalcones or α-bromocinnamates with heteroarenes
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Vinyl radicals were generated from α-bromochalcones or a-bromocinnamate ethyl ester under visible light photoredox catalyzed conditions via an oxidative quenching cycle of the iridium complex [Ir{d(CF 3)ppy}2(dtbbpy)]PF6 and subjected to cascade cyclizations with heteroarenes entailing two consecutive C-C bond formations and three C-H activations. The process is amenable to furans, benzofurans, pyrroles, and indoles, giving rise to a broad variety of novel polycyclic frameworks in high yields under mild and environmentally benign reaction conditions.
- Paria, Suva,Reiser, Oliver
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supporting information
p. 557 - 562
(2014/05/20)
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- Efficient ring-closing metathesis of alkenyl bromides: The importance of protecting the catalyst during the olefin approach
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We present the first productive ring-closing metathesis reaction that leads to the construction of cyclic alkenyl bromides. Efficient catalysis employing commercially available Grubbs II catalyst is possible through appropriate modification of the starting bromoalkene moiety.
- Gatti, Michele,Drinkel, Emma,Wu, Linglin,Pusterla, Ivano,Gaggia, Fiona,Dorta, Reto
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supporting information; experimental part
p. 15179 - 15181
(2010/12/24)
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- A novel and one step procedure for preparation of α-bromo-α,β-unsaturated carbonyl compounds
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A new one step method is developed for the preparation of α-bromo-α,β-unsaturated carbonyl compounds in moderate to good yields from corresponding α,β-unsaturated carbonyl compounds using DMP [1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(IH)-one] and te
- Ramanarayanan,Shukla, Vidyanand G.,Akamanchi
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p. 2059 - 2061
(2007/10/03)
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- Synthesis of allenes from allylic alcohol derivatives bearing a bromine atom using a palladium(0)/diethylzinc system
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A general and efficient synthesis of allenes using a palladium(0)/diethylzinc system is described. Treatment of mesylates or trichloroacetates of (E)- or (Z)-2-bromoalk-2-en-1-ols with diethylzinc in the presence of a catalytic amount of palladium(0) affords allenes bearing an aminoalkyl, alkyl, or aryl substituent(s) in good to high yields. No transfer of chirality from the stereogenic center carrying the mesyloxy group to the allene was observed.
- Ohno, Hiroaki,Miyamura, Kumiko,Tanaka, Tetsuaki,Oishi, Shinya,Toda, Ayako,Takemoto, Yoshiji,Fujii, Nobutaka,Ibuka, Toshiro
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p. 1359 - 1367
(2007/10/03)
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- A convenient and useful method of preparation of α-bromo enones from the corresponding enones using organic ammonium tribromide (OATB)
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Various acyclic α-bromo enones 2 as well as cyclic α-bromo enones 4 can be prepared from the corresponding acyclic enones 1 and cyclic enones 3 respectively, in a one-pot procedure by employing organic ammonium tribromide, such as cetyltrimethylammonium t
- Bose, Gopal,Bujar Barua, Pankaj M.,Chaudhuri, Mihir K.,Kalita, Dipak,Khan, Abu T.
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p. 290 - 291
(2007/10/03)
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