Generation of cycloheptyne during the solvolysis of cyclohexylidenemethyliodonium salt in the presence of base

被引：10

作者：

Fujita, M ^{[1
]}

Ihara, K ^{[1
]}

Kim, WH ^{[1
]}

Okuyama, T ^{[1
]}

机构：

[1] Himeji Inst Technol, Grad Sch Sci, Kamigori, Hyogo 6781297, Japan

来源：

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN | 2003年 / 76卷 / 09期

关键词：

D O I：

10.1246/bcsj.76.1849

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Solvolysis of 4-methylcyclohexylidenemethyl(phenyl)iodonium tetrafluoroborate (1) and its R isomer (69% ee) was carried out in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) in the presence of bases such as acetate, pyridine, triethylamine, and alkoxide. The reaction is much faster in TFE than in HFP. Products ill TFE include solely un-rearranged (racemized) enol ether 2 together with iodobenzene, while the main product ill HFP is ring-expanded (partially racemized) 1-alkoxycycloheptene 3. Results show that 2 is formed via alpha-elimination with alkylidenecarbene as an intermediate, while the reaction in HFP to give 3 involves a cycloheptyne intermediate that is mostly derived from an intermediate cyclohept-1-enyl cation via the E1-type pathway.

引用

页码：1849 / 1855

页数：7

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