Wang Qiong, Huang Fang, Liu Jianbiao, Wang Wenjuan, Sun Chuanzhi, Chen Dezhan
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals , Shandong Normal University , Jinan 250014 , P. R. China.
Inorg Chem. 2019 Aug 5;58(15):10217-10226. doi: 10.1021/acs.inorgchem.9b01392. Epub 2019 Jul 23.
The mechanisms of aminocarbonylations and alkoxycarbonylations in coupling of aminophenols with iodoarenes catalyzed by the bidentate phosphorus ligand Pd complexes were explored with theoretical calculations. The origins of chemoselective carbonylation mediated by ligands and bases were disclosed. According to our calculations, the bifurcation points of reaction pathways caused by different ligands and bases combinations are , a [DPPP/DIBPP]benzoylpalladium(II)iodide complex. The affinity of and adducts (KCO and DBU), as well as the substrate itself, are the predominant factors of switching from aminocarbonylation to alkoxycarbonylation. The results reveal that KCO directly exchanges iodine with and assists in hydrogen transfer in the DPPP-KCO combination, in which alkoxycarbonylation is more favorable than aminocarbonylation, while for the DIBPP-DBU combination, iodine exchange is achieved by means of the hydrogen bond formed between the carbonyl group on and the substrate amino H due to the influence of the ligand, and then iodine exchange occurs; subsequently DBU-assisted amino H transfers to complete the aminocarbonylation. The proton transfer is the step that determines the chemoselectivity in the DPPP-KCO combination. The iodine exchange determines the chemoselectivity between aminocarbonylation and alkoxycarbonylation in the DIBPP-DBU one. These results would be helpful to deeply understand the roles of each component in a chemoselective reaction in a multicomponent complex system.
