GaCl₃-Catalyzed α-Ethenylation Reaction of Ketone

Abstract

In the presence of catalytic amounts of GaCl₃ (10 mol%) and 2,6-di(t-butyl)-4-methylpyridine (10 mol%), five- or six-membered ring ketones possessing α,α′-disubstituents are ethenylated at the α-carbon with triethylsilylethyne at 180 °C. The roles of the base are to inhibit decomposition of the products and to promote protodegallation of the organogallium intermediates.

catalytic reaction - α-ethenylation - GaCl₃ - cyclic ketone - silylethyne

References

1 Millard AA. Rathke MW. J. Am. Chem. Soc.  1977,  99:  4833 

2 Chieffi A. Kamikawa K. Åhman J. Fox JM. Buchwald SL. Org. Lett.  2001,  3:  1897 

3 Seefelder M. Liebigs Ann. Chem.  1962,  652:  107 

4a Makosza M. Czyzewsky J. Jawdosiuk M. Org. Synth.  1976,  55:  99 

4b Makosza M. Tetrahedron Lett.  1966,  45:  5489 

5 Tzalis D. Knochel P. Angew. Chem. Int. Ed.  1999,  38:  1463 

6 Nakamura M. Endo K. Nakamura E. J. Am. Chem. Soc.  2003,  125:  13002 

7a Yamaguchi M. Tsukagoshi T. Arisawa M. J. Am. Chem. Soc.  1999,  121:  4074 

7b Arisawa M. Miyagawa C. Yamaguchi M. Synthesis  2002,  138 

8 Arisawa M. Akamatsu K. Yamaguchi M. Org. Lett.  2001,  3:  789 

9 Arisawa M. Miyagawa C. Yoshimura S. Kido Y. Yamaguchi M. Chem. Lett.  2001,  1080 

10 We reported a catalytic ethenylation reaction of phenols using SnCl₄: Kobayashi K. Yamaguchi M. Org. Lett.  2001,  3:  241