- 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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p. 3854 - 3858
(2014/05/06)
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- One-pot synthesis of 2,2′-bisbenzofurans using cuprous chloride as a catalyst
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A variety of novel 5,5′-disubstituted-2,2′-bisbenzofuran derivatives were synthesized by treatment of 4-substituted-2-(2- trimethylsilylethynyl)phenyl tert-butyldimethylsilyl ether analogues with CuCl as a catalyst in 62-82% isolated yields. This novel st
- Pan, Wen-Bin,Chen, Chin-Chau,Wei, Li-Lan,Wei, Li-Mei,Wu, Ming-Jung
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p. 2655 - 2657
(2013/06/05)
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