- Nickel-Catalyzed Formal Aminocarbonylation of Unactivated Alkyl Iodides with Isocyanides
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Herein, we disclose a Ni-catalyzed formal aminocarbonylation of primary and secondary unactivated aliphatic iodides with isocyanides to afford alkyl amide, which proceeds via the selective monomigratory insertion of isocyanides with alkyl iodides, subsequent β-hydride elimination, and hydrolysis process. The reaction features wide functional group tolerance under mild conditions. Additionally, the selective, one-pot hydrolysis of reaction mixture under acid conditions allows for expedient synthesis of the corresponding alkyl carboxylic acid.
- Chen, Yifeng,Huang, Wenyi,Qu, Jingping,Shrestha, Mohini,Wang, Yun,Weng, Yangyang
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p. 3245 - 3250
(2020/04/21)
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- Ligand-Free Iron-Catalyzed Carbon (sp2)-Carbon (sp2) Oxidative Homo-Coupling of Alkenyllithiums
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A new strategy was developed for the efficient synthesis of di-, tetra-, and hexa-substituted 1,3-butadienes. This one-pot procedure involves lithium-iodine exchange to generate the corresponding vinyllithium intermediates. A subsequent iron-catalyzed ligand-free oxidative homo-coupling eventually led to the formation of 1,3-butadienes in acceptable to excellent isolated yields.
- Zhong, Zhuliang,Wang, Zhi-Yong,Ni, Shao-Fei,Dang, Li,Lee, Hung Kay,Peng, Xiao-Shui,Wong, Henry N. C.
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supporting information
p. 700 - 704
(2019/02/07)
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- Switchable Synthetic Strategy toward Trisubstituted and Tetrasubstituted Exocyclic Alkenes
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An efficient and facile method for the construction of tri- or tetrasubstituted exocyclic alkenes is achieved via a Cu(I)-catalytic system. This protocol exhibits mild conditions, low-cost catalyst, good functional group tolerance, and good yields. The selectivity toward tri- or tetrasubstituted alkenes can be delicately controlled by adjustment of base and solvent. A preliminary mechanism study manifested that the reaction undergoes a radical process, where B2pin2 plays an indispensable role.
- Zhou, Sen,Yuan, Fangyuan,Guo, Minjie,Wang, Guangwei,Tang, Xiangyang,Zhao, Wentao
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p. 6710 - 6714
(2018/11/21)
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- Palladium-catalyzed alkyne insertion/Suzuki reaction of alkyl iodides
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A palladium-catalyzed alkyne insertion/Suzuki reaction with unactivated alkyl iodides is described. Under the reaction conditions, selective migratory insertion of alkynes avoids β-hydride elimination and provides a facile synthesis of stereodefined, tetrasubstituted olefins. The transformation offers broad substrate scope for both the alkyl iodide and boron nucleophile. Mechanistic studies have revealed inversion of the stereocenter for the carbon bearing the iodide.
- Monks, Brendan M.,Cook, Silas P.
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p. 15297 - 15300
(2012/11/06)
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- A direct and stereocontrolled route to conjugated enediynes
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A unified synthetic route to 3-hex-en-1,5-diynes, a key building block found in many of the enediyne antitumor agents and designed materials, was developed. The method, which relies on a carbenoid coupling-elimination strategy is tolerant of a wide range of functionalities, and was applied to the synthesis of a variety of linear and cyclic enediynes. Reaction parameters can be adjusted to control stereoselectivity of the process, producing linear enediynes from 1:12 to >100:1 E:Z ratio, and in the case of cyclic enediynes, giving the exclusively Z C-9, C-10, or C-11 products. Key features of the process are the ready availability of precursors and the mildness and efficiency of the reaction. Application of the process in the design of materials precursors and preparation of enediyne antitumor agents are presented.
- Jones, Graham B.,Wright, Justin M.,Plourde, Gary W.,Hynd, George,Huber, Robert S.,Mathews, Jude E.
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p. 1937 - 1944
(2007/10/03)
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- The Reactivity of the Highly Functionalized Copper, Zinc Reagents RCu(CN)ZnI Toward 1-Haloalkynes and Acetylenic Esters
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The highly functionalized organometallics RCu(CN)ZnI 1 react efficiently with 1-haloalkynes providing polyfunctionalized alkynes in high yields.This method has been used to prepare a pheromone of the Amathes c-nigrum in 3 steps and 64percent overall yield.The reagents 1 also add in the presence of an excess of Me3SiCl to acetylenic esters to afford polyfunctionalized C-silylated ethylenic esters.In the case of ethyl propiolate, the reaction is highly stereoselective and affords 97percent pure (E)-2-trimethylsilyl ethylenic esters.
- Yeh, Ming Chang P.,Knochel, Paul
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p. 4799 - 4802
(2007/10/02)
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- FREE RADICAL REARRANGEMENTS OF ORGANOCOBALOXIMES: ALKYNYL TO CYCLOALKYLIDENE AND HEXENYL TO CYCLOPENTYLMETHYL
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Under irradiation by tungsten light in pyridine solution, several substituted alkylcobaloximes undergo rearrangement to more stable substituted alkyl- or alkenyl-cobaloximes.When the same reactions are carried out in the presence of carbon tetrachloride or chloroform, no rearranged organobaloximes are obtained, but a variety of organic products are obtained derived from the interception of transient organic radicals by the halogenated solvent.The rearrangements are rationalised in terms of a reversible homolysis of the carbon-cobalt bond, rearrangement of the organic radical and recapture by the cobalt(II) fragment to give complexes that are more stable to irradiation than their precursors.
- Bougeard, Peter,Cooksey, Christopher J.,Johnson, Michael D.,Lewin, Melanie J.,Mitchell, Stewart,Owens, Paul A.
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p. 349 - 358
(2007/10/02)
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- Cyclizations of ω-Alkynyl Halides by Cr(II) Reduction
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Reduction of halides of the types RCC(CH2)nX with Cr(II) in aqueous DMF containing ethylenediamine proceeds by way of the intermediate radicals which cyclize regioselectively in the n=4 and n=5 cases to give substituted methylenecycloalkanes.Experimental conditions which favor longer lifetimes for the intermediate radicals (low concentrations, slow addition times, and an inverse-addition mode) result in increased cyclization.The iodides curiously give more cyclic product than the corresponding bromides.These results are discussed.
- Crandall, Jack. K.,Michaely, W. J.
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p. 4244 - 4248
(2007/10/02)
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