Control over the Chemoselectivity of Pd-Catalyzed Cyclization Reactions of (2-Iodoanilino)carbonyl Compounds
作者:Daniel Solé、Israel Fernández、Miguel A. Sierra
DOI:10.1002/chem.201102811
日期:2012.5.29
The factors that control the chemoselectivity of palladium‐catalyzed cyclization reactions of (2‐iodoanilino)carbonyl compounds have been explored by an extensive experimental computational (DFT) study. It was found that the selectivity of the process, that is, the formation of fused six‐ versus five‐membered rings, can be controlled by the proper selection of the initial reactant, reaction conditions
通过广泛的实验计算(DFT)研究已经探索了控制钯催化(2-碘代苯胺基)羰基化合物的化学选择性的因素。结果发现,该工艺的选择性,即,稠合的六元相对于五元环,可以通过初始反应物,反应条件和添加剂的适当选择被控制的形成。因此,酯或酰胺产生通过亲核加成过程酮,而另外的PhO的-离子通过α-芳基化反应导致二氢吲哚的形成。相反,在苯酚存在下,相应的酮反应物产生两种反应产物的混合物,其比例取决于所用的碱。这些过程的结果可以通过形成常见的四元的palladacycle中间体来解释,从该中间体中发生竞争性亲核加成和α-芳基化反应。苯酚在此过程中的显着作用使α-芳基化反应更容易,促进了烯醇配合物的形成,烯醇配合物通过烯醇部分的羟基与苯氧基配体的氧原子之间的分子内氢键得以稳定。而且,