- Selectivity for Alkynyl or Allenyl Imidamides and Imidates in Copper-Catalyzed Reactions of Terminal 1,3-Diynes and Azides
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Copper-catalyzed reactions of terminal 1,3-diynes with electron-deficient azides to generate either 3-alkynyl or 2,3-dienyl imidamides and imidates are described. The selectivity depends on the diyne substituents and the nucleophile that reacts with the ketenimide intermediate generated from the corresponding triazole precursor. Reactions of 1,3-diynes containing a propargylic acetate afford [3]cumulenyl imidamides, while reactions using methanol as the trapping agent selectively generate 2,3-dienyl imidates. Five-membered heterocycles were obtained from 1,3-diynes containing a homopropargylic hydroxyl or amine substituent.
- Ghorai, Sourav,Lee, Daesung
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p. 697 - 701
(2021/02/01)
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- The first metathesis of C-C single bonds in homogeneous solution: Titanocene-mediated and photocatalyzed cleavage and recombination of disubstituted butadiynes
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The activation and cleavage of the central C-C bond of substituted butadiynes has been combined for the first time with a subsequent coupling reaction of the resulting alkynyl units: In the presence of an equimolar amount of 'Cp2Ti', the butadiynes 1 and 2 afford after workup the asymmetrically substituted diyne 3. This photocatalyzed metathesis also proceeds in the reversed direction.
- Pulst, Siegmar,Kirchbauer, Frank G.,Heller, Barbara,Baumann, Wolfgang,Rosenthal, Uwe
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p. 1925 - 1927
(2007/10/03)
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