Tris(trimethylsilyl)silyl Radical Induced Bicyclization of 1,6-Dienes and 1,6-Enynes Providing 3,3-Bis(trimethylsilyl)-3-silabicyclo[3.3.0]octanes and 3-Silabicyclo[3.3.0]oct-1-enes
the second olefinic bond of the diene 1 and forms cyclopentylalkyl radical 4. Using a low concentration of the hydrogen donor 2, a radical substitutionreaction at the Si-center of cis-4 occurs and yields the bicyclic silane 6. The rate of this homolytic substitution at the Si-atom is 2.4 · 105 s-1 (80°).
三(三甲基甲硅烷基)硅烷(2)是一种通过自由基链机理操作的有效的1,6-二烯1的氢化硅烷化剂。中间烷基3攻击二烯1的第二烯键并形成环戊基烷基4。使用氢供体的浓度低2中,在所述Si-中心自由基取代反应的顺式- 4发生并产生双环硅烷6。在硅原子上这种均质取代的速率为2.4·10 5 s -1(80°)。
Tris(trimethylsilyl)silyl Radical Induced Bicyclization of 1,6-Dienes and 1,6-Enynes Providing 3,3-Bis(trimethylsilyl)-3-silabicyclo[3.3.0]octanes and 3-Silabicyclo[3.3.0]oct-1-enes
Treatment of 1,6-dienes with tris(trimethylsilyl)silane in the presence of triethylborane or AIBN afforded 3,3-bis(trimethylsilyl)-3-silabicyclo[3.3.0]octanes in addition to monocyclized cyclopentanes. Bicyclization of 1,6-enynes provided the corresponding 3-silabicyclo[3.3.0]oct-1-enes.