Subscribe to RSS
Please copy the URL and add it into your RSS Feed Reader.
https://www.thieme-connect.de/rss/thieme/en/10.1055-s-00000131.xml
Synfacts 2010(6): 0644-0644
DOI: 10.1055/s-0029-1219879
DOI: 10.1055/s-0029-1219879
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Copper(II) Bromide/BoronTrifluoride Cocatalyzed Synthesis of Benzofurans
Y. Liu, M. Wang*, H. Yuan, Q. Liu*
Northeast Normal University, Changchun, P. R. of China
Further Information
Publication History
Publication Date:
20 May 2010 (online)
Significance
A formal [3+2] cycloaddition between CuBr2-activated α-EWG ketene dithioacetals 1 and BF3-activated p-quinones 2 provides benzofurans. Optimized reaction conditions were established using CuBr2 (20 mol%)/BF3 (10 mol%) in MeCN at room temperature. p-Quinones containing both electron-withdrawing and -donating substituents proved to be effective and gave benzofurans in good yields. On the other hand, o-quinone proved not to be a suitable substrate. Ketene dithioacetals 1 with a range of EWG were shown to be effective reaction partners. A possible mechanism for the catalytic activation of CuBr2 on α-EWG ketene dithioacetals 1 was proposed.