Lewis Acid Promoted Reactions of Ethenetricarboxylates with Allenes: Synthesis of Indenes and γ-Lactones via Conjugate Addition/Cyclization Reaction
作者:Shoko Yamazaki、Yuko Yamamoto、Yugo Fukushima、Masachika Takebayashi、Tetsuma Ukai、Yuji Mikata
DOI:10.1021/jo1009855
日期:2010.8.6
Indenes are important core structures in organic chemistry. Few simple arylallenes have been used to construct indene skeletons by Friedel Crafts reaction. Lewis acid catalyzed reaction of ethenetricarboxylates 1 and arylallenes has been examined in this study. The reaction of arylallenes and ethenetricarboxylate triesters with SnCl4 gave indene derivatives efficiently, via a conjugate addition/Friedel-Crafts cyclization reaction. On the other hand, the reactions of 1,1-diethyl 2-hydrogen ethenetricarboxylate and arylallenes or alkylallenes with SnCl4 at -78 degrees C or room temperature and subsequent treatment with Et3N gave gamma-lactones. The reactions of triethyl ethenetricarboxylate and 1,1-dialkylallenes with SnCl4 at room temperature also gave gamma-lactones.