model 5-silabicyclo[3.2.0]hepta-1,3,6-triene was calculated at the MP2/6-31+G(d,p)//B3LYP/6-31+G(d) level (30.2 kcal/mol) to be comparable to that for parent bicyclo[3.2.0]hepta-1,3,6-triene (30.7 kcal/mol). Despite the high steric strain, 2 was stable enough to be kept intact for several months in the air. The high stability is ascribed to the effective steric protection of the ring system by the bulky
具有高度应变桥头双键的含
硅稠合
双环化合物,2,3,6,7-四-叔丁基-4-(叔丁基二甲基甲
硅烷基)-5-(叔丁基二甲基甲
硅烷氧基)-5-
硅杂环[3.2 .0]hepta-1,3,6-triene (2), 由 1,2-bis-tert-butyl-4,4-bis(tert-butyldimethylsilyl)-4-silatrifulvene (3) 反应定量合成与二叔丁基
环丙烯酮 (4) 在 80 摄氏度。 2 的 X 射线晶体学分析不仅证实了具有与
硅杂
环丁烯环稠合的
硅杂
环戊二烯 (silole) 环的双环结构,而且双键周围的显着变形;不饱和桥头碳周围的键角总和为 333 度。在 MP2/6-31+G(d,p)//B3LYP/6-31+G(d ) 级 (30。2 kcal/mol) 与母体双环 [3.2.0] 庚-1,3,6-
三烯 (30.7 kcal/mol) 相当。尽管空间位阻高,但