作者:Faiz Ahmed Khan、Jyotirmayee Dash、Ch. Sudheer、Nilam Sahu、Karuppasamy Parasuraman
DOI:10.1021/jo0507385
日期:2005.9.1
The two oxa bridges are syn to each other, separated by central cyclohexane and cycloheptane rings in 10 and 27, while they are anti to each other and are separated by central cyclopentane and furan rings in 28 and 29. In the case of the highly symmetric bis-oxa-bridged derivative 10 the two syn oxa bridges constrain the central cyclohexane ring into the boat form. The endo,anti,endo 2:1 bis adducts of
设计了一种立体选择性策略,用于用氧桥取代四卤代降冰片基衍生物的1,2-二卤代烯烃桥,所述氧桥涉及逐步控制的氧化,如此形成的二酮的裂解以及两个桥头卤素的分子内S N 2的迭代式置换。四个高度应变五环双氧杂桥接衍生物的合成10,27,28,和29与有趣的结构变化被呈现。这两个氧杂桥彼此同构,在10和27中被中央环己烷和环庚烷环隔开,而在它们之间彼此相反并被中央环戊烷和呋喃环隔开。28和29。在高度对称的双-氧杂桥联衍生物10的情况下,两个顺式氧杂桥将中央环己烷环约束为船形。首次制备了1,2,3,4-四卤代5,5-二甲氧基环戊-1,3-二烯与环戊二烯的内,反,内2:1双加合物,而先前未开发的双加合物的反应活性揭示了呋喃和环庚三烯的衍生物。