| Summary: | 碩士 === 輔仁大學 === 化學系 === 84 === (2-Bromovinyl)trimethylsilane (2) has been synthesized by
radical additionof trimethylsilylacetylene with dry hydrogen
bromide. 1-Bromo-2,2-dichloro-3-trimethylsilylcyclopropane (3)
is generated by dichlorocarbene addition of 2. Compound 3
reacts with methyllithium in THF solution at -78 C to produce1-
chloro-3-trimethylsilylcyclopropene (6), then be trapped by
cyclopentadieneas the precursors of 1,3-fused tricyclic
cyclopropenes, tricyclo[3.2.1.02,4]octa-2,6-diene and
tricyclo[3.2.1.02,4]oct-2-ene. Compound 6 undergoes enereaction
at -40 C to form ene dimer which is trapped by cyclopentadiene.
Thestereoselectivity of ene dimerization of 6 did not obey the
estimation, under-went the chlorine stablized carbocation, it
formed 2-chloro-3-(2-chloro-3-tri-methylsilylcyclopropyl)-4-
trimethylsilyltricyclo[3.2.1.02,4]oct-6-ene. The similar
compounds, 1-chloro-2-trimethylsilylcyclopropene and 1-bromo-2-
chlorocyclopropene, in solution condition do not undergo ene
reactions togive dimers at room temperature.
|
|---|
