Molybdenum-Catalyzed Ring-Closing Metathesis of Allenynes
摘要:
A ring-closing metathesis reaction of allenynes occurred at room temperature in the presence of a molybdenum alkylidene complex to give ring-closed vinylallenes. The vinylallene skeletons were constructed by a metathesis-type reaction between the alkyne moiety and the proximal carbon-carbon double bond of the allene moiety.
GaCl<sub>3</sub>-Catalyzed Allenyne Cycloisomerizations to Allenenes
作者:Sang Ick Lee、So Hee Sim、Soo Min Kim、Kwang Kim、Young Keun Chung
DOI:10.1021/jo061318y
日期:2006.9.1
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
[Graphics]Cycloisomerizations of allenynes to allenenes have been studied in the presence of catalytic amounts of [Hg(OTf)(2)] in acetonitrile. The catalytic system is quite effective for terminal 1,6-allenynes: allenenes were obtained in reasonable to high yields. However, treatment of allenynes with disubstituents at the allenic terminal carbon yielded a triene and/ or allenene as a major product(s) depending upon the substituents.