GaCl3-catalyzed allenyne cycloisomerizations to allenenes.
Cycloisomerizations of allenynes to allenenes have been studied in the presence of catalytic amounts of [Au(PPh3)]SbF6 in dichloromethane or GaCl3 in toluene. Both catalytic systems are quite effective for terminal 1,6-allenynes. However, they showed different reactivities toward allenynes with di-substituents at the allenic terminal carbon. For the GaCl3-catalyzed reactions, allenenes were obtained in reasonable to high yields. However, for a Au(I)-catalyzed reaction, a triene was obtained in a poor yield. Thus, GaCl3 serves as an effective catalyst for the cycloisomerization of allenynes bearing a terminal alkyne to give cyclic allenenes in reasonable to high yields.
Lee
Sang Ick
SI
Intelligent Textile System Research Center and Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea.
Sim
So Hee
SH
Kim
Soo Min
SM
Kim
Kwang
K
Chung
Young Keun
YK