Diisobutylaluminum Hydride Promoted Cyclization of <i>o</i>-(Trimethylsilylethynyl)styrenes to Indenes
作者:Hidenori Kinoshita、Nobuyoshi Hirai、Katsukiyo Miura
DOI:10.1021/jo501383v
日期:2014.9.5
The reaction of o-(trimethylsilylethynyl)styrenes with diisobutylaluminum hydride (DIBAL-H) provides 2-trimethylsilyl-1H-indenes efficiently. The cyclization mechanism involves regioselective hydroalumination of the alkynyl moiety, geometrical isomerization of the alkenylaluminums formed, and intramolecular carboalumination. With substrates bearing a 2-(trimethylsilyl)ethenyl group (R-1 = Me3Si, R-2 = R-3 = H), bis-silylated benzofulvenes are obtained upon treatment of the reaction mixture with an excess amount of benzaldehyde.