Photosensitizer‐Free Visible‐Light‐Mediated Gold‐Catalyzed 1,2‐Difunctionalization of Alkynes |
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| Authors: | Long Huang Dr Matthias Rudolph Dr Frank Rominger Prof?Dr A Stephen K Hashmi |
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| Affiliation: | 1. Organisch-Chemisches Institut, Universit?t Heidelberg, Heidelberg, Germany;2. http://www.hashmi.de;3. Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia |
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| Abstract: | Under visible‐light irradiation, the gold‐catalyzed intermolecular difunctionalization of alkynes with aryl diazonium salts in methanol affords a variety of α‐aryl ketones in moderate to good yields. In contrast to previous reports on gold‐catalyzed reactions that involve redox cycles, no external oxidants or photosensitizers are required. The reaction proceeds smoothly under mild reaction conditions and shows broad functional‐group tolerance. Further applications of this method demonstrate the general applicability of the arylation of a vinyl gold intermediate instead of the commonly used protodemetalation step. This step provides facile access to functionalized products in one‐pot processes. With a P,N‐bidentate ligand, a stable aryl gold(III) species was obtained, which constitutes the first direct experimental evidence for the commonly postulated direct oxidative addition of an aryl diazonium salt to a pyridine phosphine gold(I) complex. |
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| Keywords: | alkynes arylations gold photochemistry α -aryl ketones |
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