Cycloaddition of Tungsten-1-3-Furyl Compounds with Alkenes and Alkynes: Syntheses and Ring Cleavage of Tungsten-
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- 作者：Lin-Hung Shiu ; Hsin-Kuo Shu ; Da-Hsin Cheng ; Heh-Long Hwang ; Sue-Lein Wang ; Fen-Lin Liao ; and Rai-Shung Liu
- 刊名：Organometallics
- 出版年：1998
- 出版时间：September 14, 1998
- 年：1998
- 卷：17
- 期：19
- 页码：4206 - 4212
- 全文大小：120K
- 年卷期：v.17,no.19(September 14, 1998)
- ISSN：1520-6041
文摘
Cycloaddition of tungsten-
1-3-furyl compounds with a variety of organic alkenes andalkynes proceeds smmothly at ambient conditions, yielding tungsten-1-oxabicyclo[2.2.1]heptene and -1-oxabicyclo[2.2.1]heptadiene compounds in high regioselectivities andstereoselectivities. The cycloaddition is proposed to proceed via a mechanism involving azwitterion intermediate. Cleavage of oxygen bridges of 1-oxabicyclo[2.2.1]heptenes and 1-oxabicyclo[2.2.1]heptadienes occurs on treatment of CF3SO3H and Lewis acid, leading toatypical carbon-carbon bond scission and deoxygenation reactions to give highly substitutedbenzene and furan derivatives, respectively. The role of the tunsten fragment in thesedemetalation reactions is discussed in detail.
1-3-furyl compounds with a variety of organic alkenes andalkynes proceeds smmothly at ambient conditions, yielding tungsten-1-oxabicyclo[2.2.1]heptene and -1-oxabicyclo[2.2.1]heptadiene compounds in high regioselectivities andstereoselectivities. The cycloaddition is proposed to proceed via a mechanism involving azwitterion intermediate. Cleavage of oxygen bridges of 1-oxabicyclo[2.2.1]heptenes and 1-oxabicyclo[2.2.1]heptadienes occurs on treatment of CF3SO3H and Lewis acid, leading toatypical carbon-carbon bond scission and deoxygenation reactions to give highly substitutedbenzene and furan derivatives, respectively. The role of the tunsten fragment in thesedemetalation reactions is discussed in detail.