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Lewis acid-mediated intramolecular addition of silyl enol ethers to internal unactivated alkynes
被引:15
|作者:
Imamura, K
[1
]
Yoshikawa, E
[1
]
Gevorgyan, V
[1
]
Sudo, T
[1
]
Asao, N
[1
]
Yamamoto, Y
[1
]
机构:
[1] Tohoku Univ, Grad Sch Sci, Dept Chem, Sendai, Miyagi 9808578, Japan
关键词:
Lewis acid;
silyl enol ethers;
carbocyclization;
alkynes;
D O I:
10.1139/cjc-79-11-1624
中图分类号:
O6 [化学];
学科分类号:
0703 ;
摘要:
The EtAlCl2-mediated intramolecular addition of silyl enol ethers to both terminal and internal unactivated alkynes, bearing alkyl and phenyl susbstituents at the alkyne moiety, gave mono- and bicyclic beta,gamma -unsaturated ketones in good to excellent yields. On the other hand, the silyloxy-substituted cyclic vinylsilanes were obtained in moderate to high yields when the reactions were catalyzed by B(C6F5)(3) in the presence of triethylsilane. All the reactions proceeded via endo-fashion exclusively. The mechanisms of these regiospecific Lewis acid-assisted carbocyclizations are proposed.
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页码:1624 / 1631
页数:8
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