AuI-Catalyzed Tandem [3,3] Rearrangement-Intramolecular Hydroarylation: Mild and Efficient Formation of Substituted Indenes

摘要

Recent reports have highlighted the use of gold(I) and gold(III) complexes as efficient homogeneous catalysts in several organic transformations.[1] Notably, gold catalysts, in both oxidation states, enable the cycloisomerization of enynes.[2] Based on these earlier studies, we reasoned that the electron-rich phenyl ring could replace an alkene moiety and lead to valuable cyclized products. Surprisingly, the only related examples of intramolecular hydroarylation employ a heteroatom-containing tether to provide indoles, benzofurans, or coumarins.[3] Carbocycles, especially indenes, are compounds of great interest as synthetic targets and building blocks for pharmaceutical[4] and materials chemistry.[5] As the inter- or intramolecular formation of indenes usually requires high temperature and/or a prolonged reaction time,[6] a mild and efficient assembly protocol would be highly desirable.