- Homologation of Electron-Rich Benzyl Bromide Derivatives via Diazo C-C Bond Insertion
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The ability to manipulate C-C bonds for selective chemical transformations is challenging and represents a growing area of research. Here, we report a formal insertion of diazo compounds into the "unactivated"C-C bond of benzyl bromide derivatives catalyzed by a simple Lewis acid. The homologation reaction proceeds via the intermediacy of a phenonium ion, and the products contain benzylic quaternary centers and an alkyl bromide amenable to further derivatization. Computational analysis provides critical insight into the reaction mechanism, in particular the key selectivity-determining step.
- Alegre-Requena, Juan V.,De Lescure, Louis,Modak, Atanu,Paton, Robert S.,Race, Nicholas J.,Rynders, Kathryn J.
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supporting information
(2021/12/27)
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- Facile One-Pot Access to α-Diazo-β-ketosulfones from Sulfonyl Chlorides and α-Haloketones
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A convenient one-pot approach to the preparation of α-diazo-β-ketosulfones from sulfonyl chlorides is described. It involves the conversion of the sulfonyl chloride to sodium sulfinate, alkylation of the latter with α-haloketones followed by diazo transfer using the 'sulfonyl-azide-free' ('SAFE') protocol in aqueous medium. The simple and expedient method relies on readily available starting materials and provides facile access to a wide variety of valuable diazo reagents for organic synthesis.
- Dar'In, Dmitry,Kantin, Grigory,Bakulina, Olga,Krasavin, Mikhail
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p. 2259 - 2266
(2020/08/26)
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- Enoldiazosulfones for Highly Enantioselective [3 + 3]-Cycloaddition with Nitrones Catalyzed by Copper(I) with Chiral BOX Ligands
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Enoldiazosulfones undergo [3 + 3]-cycloaddition with nitrones when catalyzed by copper(I) catalysts, but not with dirhodium(II) catalysts. Under mild reaction conditions with chiral bisoxazoline ligands, copper(I) catalysts produce 1,2-oxazine-sulfone derivatives in high yields and enantioselectivities. Dirhodium(II) catalysts form stable donor-acceptor cyclopropenes that undergo uncatalyzed [3 + 2]-cycloaddition reactions with nitrones.
- Adly, Frady G.,Marichev, Kostiantyn O.,Jensen, Joseph A.,Arman, Hadi,Doyle, Michael P.
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supporting information
p. 40 - 44
(2019/01/11)
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- Copper-catalyzed chemoselective cross-coupling reaction of thioamides and α-diazocarbonyl compounds: Synthesis of enaminones
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The development of operationally simple and cost-effective methods for C[sbnd]C bond formation reactions are highly important in pharmaceutical, agrochemical and material research. In this article we describe the first copper-catalyzed cross-coupling reaction of thioamides with acceptor/acceptor-substituted and acceptor-only substituted α-diazocarbonyl compounds to yield enaminones. The reaction shows broad substrate scope in terms of thioamides and diazocarbonyl compounds. Primary, secondary and tertiary thioamides all give enanminones when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, α-diazoketoamides, α-diazoesteramides, α-diazoketosulfones and α-diazomonoketones.
- Pal, Arpal,Koduri, Naga D.,Wang, Zhiguo,Quiroz, Erika Lopez,Chong, Alexandra,Vuong, Matthew,Rajagopal, Nisha,Nguyen, Michael,Roberts, Kenneth P.,Hussaini, Syed R.
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supporting information
p. 586 - 589
(2017/01/16)
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- Synthesis and Chemistry of Donor/Acceptor-Substituted Cyclopropenes
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Rhodium(II) acetate, or trifluoroacetate-catalyzed decomposition of 1-diazo-2-(trialkylsiloxy)propenes with electron-withdrawing groups at the 1-position results in the formation of highly reactive cyclopropenes.These cyclopropenes contain both donor and acceptor substituents on the alkene and are very susceptible to ring opening and fragmentation reactions.Nevertheless, when appropriately functionalized with bulky substituents they can be of sufficient stability to be isolated and characterized.
- Davies, Huw M. L.,Houser, Jeffrey H.,Thornley, Craig
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p. 7529 - 7534
(2007/10/03)
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