Stereoselective Synthesis of 1,3-Diaminotruxillic Acid Derivatives: An Advantageous Combination of CH-<i>ortho</i>
-Palladation and On-Flow [2+2]-Photocycloaddition in Microreactors
作者:Elena Serrano、Alberto Juan、Angel García-Montero、Tatiana Soler、Francisco Jiménez-Márquez、Carlos Cativiela、M. Victoria Gomez、Esteban P. Urriolabeitia
DOI:10.1002/chem.201503742
日期:2016.1.4
The stereoselective synthesis of ε‐isomers of dimethyl esters of 1,3‐diaminotruxillic acid in three steps is reported. The first step is the ortho‐palladation of (Z)‐2‐aryl‐4‐aryliden‐5(4H)‐oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho‐CH bond of the 4‐arylidene ring in carboxylic acids. The second step is
报道了三步法合成1,3-二氨基苯甲酸的二甲酯的ε-异构体的立体选择性合成。第一步是在邻位的(-palladation Ž)-2-芳基-4- aryliden-5(4 ħ)-oxazolones 1,得到双核配合物2具有桥接羧酸盐。发生该反应通过的区域选择性激活邻-C 在羧酸的4-亚芳基环上的H键。第二个步骤是恶唑酮骨架的环外CC键的在[2 + 2] -photocycloaddition 2,得到相应的双核邻-palladated环丁烷3。通过在流动微反应器中使用具有不同波长(465、525或625 nm)的LED光源,可以非常有效地执行此关键步骤。最后一步涉及在甲醇中加氢使3脱钯,得到单异构体ε-1,3-二氨基truxillicic酸衍生物。