Synthesis of polycyclic polyfunctionalized carbocycles by a cobalt(I)‐initiated tandem diels–alder reaction sequence
作者:Gerhard Hilt、Steffen Lüers、Kurt Polborn
DOI:10.1560/8e4x-0u34-mqyd-0h20
日期:2001.12
sequence, the cobalt-catalyzed neutral homo Diels–Alder reaction of 2,5-norbornadiene can be used to generate polycyclic cycloaddition adducts. A sequential triple Diels–Alder reaction sequence can be realized when norbornadiene is reacted with the excess of the conjugated enynes under cobalt(I) catalysis. In a homo Diels–Alder, neutral Diels–Alder, normal Diels–Alder reaction sequence, the intermediately
无环1,3-二烯与共轭烯炔的钴(I)催化中性Diels-Alder反应可用于在温和的条件下以良好的收率生成包含1,3-二烯亚结构的二级二氢芳族1,4,8-三烯反应条件。这些1,3-二烯可以与正常Diels-Alder反应中的反应性亲二烯体转化为多环化合物。在相似的串联Diels–Alder序列中,钴催化的2,5-降冰片二烯的中性均相Diels–Alder反应可用于生成多环环加成加合物。当降冰片二烯与过量的共轭烯炔在钴(I)催化下反应时,可以实现顺序的三重Diels–Alder反应顺序。在同构Diels–Alder,中性Diels–Alder,正常Diels–Alder反应序列中,中间形成的加合物与活化的亲二烯体反应,以短序列产生多环化合物。通过X射线分析确定了几种产品的结构。这表明在串联反应序列中主要形成内产物,而在三重Diels–Alder反应序列中外形成物占主导地位。