- Tandem Ullmann-Goldberg Cross-Coupling/Cyclopalladation-Reductive Elimination Reactions and Related Sequences Leading to Polyfunctionalized Benzofurans, Indoles, and Phthalanes
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On exposure to a combination of Cu[I]- and Pd[0]-based catalysts, compounds such as 1 and 7 engage in tandem Ullmann-Goldberg cross-coupling and cyclopalladation-reductive elimination reactions to give benzofurans such as 8. Related reactions involving hetero-Michael additions of o-halogenated phenols or anilines to propiolates and the Pd[0]-catalyzed cyclization of the resulting conjugates provide, in a one-pot process, alternately functionalized benzofurans, indoles, or phthalanes.
- Khan, Faiyaz,Fatima, Mehvish,Shirzaei, Moheb,Vo, Yen,Amarasiri, Madushani,Banwell, Martin G.,Ma, Chenxi,Ward, Jas S.,Gardiner, Michael G.
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Read Online
- Experimental studies on the selective β-c-h halogenation of enones
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Here we describe the realization of a one-pot protocol for the β-C-H halogenation of cyclic enones via umpolung of the β-carbon. The developed method includes hydrazone formation and selective β-halogenation (bromination, chlorination) with N-bromosuccini
- Huber, Tatjana,Kaiser, Daniel,Rickmeier, Jens,Magauer, Thomas
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p. 2281 - 2294
(2015/03/18)
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- Design, synthesis, and diversification of 3,5-substituted enone library
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This paper describes the synthesis of a 300 member library of 3,5-substituted enones. The synthesis starts with 6 different bromoenones that are accessed from the corresponding 1,3 diones. These bromides are then diversified by Suzuki coupling with a variety of aromatic and vinyl boronic acids. Additionally a small series of triazoles was synthesized by a Sonogashira coupling reaction dipolar cycloaddition sequence. The library was analyzed by principal component analysis to examine its diversity.
- Khalaf, Juhienah,Estrella-Jimenez, Maria E.,Shashack, Matthew J.,Phatak, Sharangdhar S.,Zhang, Shuxing,Gilbertson, Scott R.
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scheme or table
p. 351 - 356
(2011/08/21)
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- VILSMEIER REAGENTS: PREPARATION OF β-HALO-α,β-UNSATURATED KETONES
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A new method for the preparation of β-chloro and β-bromo-α,β-unsaturated ketones from β-diketones is described.Utilizing Vilsmeier reagents (prepared from N,N-dimethylformamide and oxalyl chloride or oxalyl bromide) β-halo-α,β-unsaturated ketones are isolated in excellent yields.
- Mewshaw, Richard E.
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p. 3753 - 3756
(2007/10/02)
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- Synthesis of β-chloro, β-bromo, and β-iodo α,β-unsaturated ketones
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A new, efficient method for the preparation of β-chloro, β-bromo, and β-iodo α,β-unsaturated ketones is described.The method involves the reaction of β-diketones or α-hydroxymethylenecycloalkanones with triphenylphosphine dihalides in the presence of trie
- Piers, Edward,Grierson, John R.,Lau, Cheuk Kun,Nagakura, Isao
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p. 210 - 223
(2007/10/02)
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- Use of Protected β-Bromocyclopentenones and β-Bromocyclohexenones as β-Acylvinyl Anion Equivalents
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Ethylene glycol ketals of the 3-bromocyclohex-2-en-1-one as well as its 2-methyl, 2-n-propyl, and 5,5-dimethyl derivatives have been prepared, and their reactions with butyllithium were studied.The organolithium reagents derived from the above compounds react with a variety of electrophiles to afford after acid hydrolysis the corresponding 3-substituted cyclohexenones.Attempts to prepare the ethylene glycol ketal of 2-methyl-3-bromocyclopent-2-en-1-one gave a low yield of the bromoketal.However, dithioketals of 3-bromocyclopent-2-en-1-one and its 2-methyl derivativecould be prepared in good yield.The metalation chemistry of the dithioketals in both the five- and six-membered-ring series was examined.The functionalization chemistry of the resulting organolithium compounds afforded after dithioketal hydrolysis 3-functionalized cyclohex-2-en-1-ones and cyclopent-2-en-1-ones.Several limitations of the chemistry using allyl bromide and cyclohexenone as electrophiles are noted.
- Shih, Chuan,Swenton, John S.
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p. 2825 - 2832
(2007/10/02)
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