Chemoselectivity Control: Gold(I)‐Catalyzed Synthesis of 6,7‐Dihydrobenzofuran‐4(5H)‐ones and Benzofurans from 1‐(Alkynyl)‐7‐oxabicyclo[4.1.0]heptan‐2‐ones |
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| Authors: | Tao Wang Shuai Shi Dr Mie Højer Vilhelmsen Tuo Zhang Dr Matthias Rudolph Prof?Dr A Stephen K Hashmi |
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| Institution: | 1. Organisch‐Chemisches Institut, Ruprecht‐Karls‐Universit?t Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49)?6221‐54‐4205;2. Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia) |
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| Abstract: | New and chemoselective gold(I)‐catalyzed transformations of 1‐(arylethynyl)‐7‐oxabicyclo4.1.0]‐ heptan‐2‐ones were developed. Two completely different products—6,7‐dihydrobenzofuran‐4(5H)‐ones and benzofurans—could be obtained from the same starting material. The selectivity is determined by the ligand of the gold catalyst: triphenylphosphine delivers 6,7‐dihydrobenzofuran‐4(5H)‐ones, and 1,3‐bis(diisopropylphenyl)imidazol‐2‐ylidene leads to benzofurans. Eleven examples of each case are provided. The mechanistic suggestions for the pathways to both product types are supported by isotope labeling experiments. |
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| Keywords: | annulation chemoselectivity gold ligand effects synthetic methods |
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