- A Hg(OTf)2-Catalyzed Enolate Umpolung Reaction Enables the Synthesis of Coumaran-3-ones and Indolin-3-ones
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The potential of mercury catalysis has been extended to the arena of enolate umpolung reactions for the first time by the generation of enolonium species via Hg(OTf)2-catalyzed N-oxide addition to alkynes. The enolonium species formed can undergo intramolecular nucleophilic attack by hydroxyl or amino groups, leading to the synthesis of various coumaran-3-ones and indolin-3-ones.
- Dai, Ning,Hu, Weican,Qian, Guoying,Rong, Zhouting
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supporting information
p. 3286 - 3290
(2020/04/21)
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- Cyclization of gold acetylides: Synthesis of vinyl sulfonates via gold vinylidene complexes
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Differently substituted terminal alkynes that bear sulfonate leaving groups at an appropriate distance were converted in the presence of a propynyl gold(I) precatalyst. After initial formation of a gold acetylide, a cyclization takes place at the β-carbon atom of this species. Mechanistic studies support a mechanism that is related to that of dual gold-catalyzed reactions, but for the new substrates, only one gold atom is needed for substrate activation. After formation of a gold vinylidene complex, which forms a tight contact ion pair with the sulfonate leaving group, recombination of the two parts delivers vinyl sulfonates, which are valuable targets that can serve as precursors for cross-coupling reactions, for example. Gold vinylidene intermediates are generated by the cyclization of gold acetylides that carry a sulfonate leaving group. This result demonstrates for the first time that the formation of these species is not restricted to a dual activation mode. The cyclization products obtained herein contain a vinyl sulfonate moiety, which makes them useful building blocks for cross-coupling reactions.
- Bucher, Janina,Wurm, Thomas,Nalivela, Kumara Swamy,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 3854 - 3858
(2014/05/06)
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- Halocarbon Chemistry. !. (2-Hydroxyaryl)acetylenes from Haloethyl Aryl Ethers. A New O to C Rearrangement.
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A new base-induced (BuLi) oxygen-to carbon rearrangement is described which involves the direct conversion of phenyl tetra(or tri)haloethyl ethers and the related intermediate phenoxyalkynes to the corresponding 1-(2-hydroxyphenyl)alkynes in good to excel
- Subramanian, Raghupathi,Johnson, Francis
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p. 5430 - 5432
(2007/10/02)
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