Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstr. 6, D-38678 Clausthal-Zellerfeld, Germany.
Molecules. 2010 May 10;15(5):3402-10. doi: 10.3390/molecules15053402.
The synthetic potential of stereoselective, palladium-catalyzed hydro(het)arylation reactions of bi-, tri- and tetracyclic (hetero)alkenes in the presence of phospines and arsines as highly efficient ligands was studied. The mechanism of this reductive Heck reaction becomes more complex in the case of benzonorbornenes. Hydroarylation of diazabicyclo-[2.2.1]heptenes provides a stereoselective access to aryldiaminocyclopentanes. Electron-deficient arylpalladium complexes shift the reaction towards the product of a formal 1,2-hydrazidoarylation reaction of 1,3-cyclopentadiene by a stereoselective C-N cleavage. Due to steric reasons, rigid bicyclo[2.2.2]octenes react slower in hydroarylation reactions than the corresponding bicyclo[2.2.1]heptenes. The more flexible bicyclo[4.2.2]decene system already tends to undergo domino-Heck reactions, even under reductive conditions. When a tetracyclic cis-allylcyclopropane is carbopalladated in the presence of formates, the neighboring cyclopropane ring is attacked in the first reported example of a pi,sigma domino-Heck reaction.
研究了在膦和砷作为高效配体存在的情况下，双环、三环和四环（杂）烯烃的立体选择性钯催化氢（杂）芳基化反应的合成潜力。苯并降冰片烯的情况下，这种还原 Heck 反应的机理变得更加复杂。二氮杂双环-[2.2.1]庚烯的氢芳基化提供了一种对芳基二氨基环戊烷的立体选择性方法。缺电子芳基钯配合物通过立体选择性 C-N 裂解将反应转移到 1,3-环戊二烯的形式 1,2-重氮芳基化反应的产物。由于空间位阻的原因，刚性双环[2.2.2]辛烯在氢芳基化反应中的反应速度比相应的双环[2.2.1]庚烯慢。更灵活的双环[4.2.2]癸烯体系已经倾向于发生多米诺 Heck 反应，即使在还原条件下也是如此。当在甲酸盐存在下对四环顺式烯丙基环丙烷进行碳钯化时，在首例报道的π,σ 多米诺 Heck 反应中，相邻的环丙烷环受到攻击。
