Gold‐Catalyzed Intramolecular [3+2] Cycloadditions of 1‐Aryl‐1‐allene‐6‐enes |
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| Authors: | Rupsha Chaudhuri Hsin‐Yi Liao Prof. Dr. Rai‐Shung Liu Prof. Dr. |
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| Affiliation: | 1. Department of Chemistry, National Tsing‐Hua University, Hsinchu (Taiwan, ROC);2. Department of Science Education, National Taipei University of Education, Taipei (Taiwan, ROC) |
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| Abstract: | Treatment of 1‐aryl‐1‐allen‐6‐enes with [PPh3AuCl]/AgSbF6 (5 mol %) in CH2Cl2 at 25 °C led to intramolecular [3+2] cycloadditions, giving cis‐fused dihydrobenzo[a]fluorene products efficiently and selectively. The reactions proceeded with initial formation of trans/cis mixtures of 2‐alkyl‐1‐isopropyl‐2‐phenyl‐1,2‐dihydronaphthalene cations B, which were convertible into the desired cis‐fused cycloadducts through the combined action of a gold catalyst and a Brønsted acid. Theoretic calculation supports the participation of the trans‐B cation as reaction intermediate. Although HOTf showed similar activity towards several 1‐aryl‐1‐allen‐6‐enes, it lacks generality for this cycloaddition reaction. |
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| Keywords: | allenes cycloaddition gold heterogeneous catalysis |
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