DFT Study of the Mechanisms of Iron-Catalyzed Regioselective Synthesis of α-Aryl Carboxylic Acids from Styrene Derivatives and CO2

详细信息    查看全文

• 作者：Qinghua Ren ; Ningning Wu ; Ying Cai ; Jianhui Fang
• 刊名：Organometallics
• 出版年：2016
• 出版时间：December 12, 2016
• 年：2016
• 卷：35
• 期：23
• 页码：3932-3938
• 全文大小：494K
• ISSN：1520-6041

文摘

The mechanisms of highly regioselective iron(II)-catalyzed synthesis of α-carboxylic acids from alkene derivatives and CO₂ have been investigated using density functional theory (DFT) calculations at the B3LYP-D3 level. The results show that the overall catalytic cycle includes β-hydride elimination, hydrometalation, oxidative addition of EtMgBr, reductive elimination, and carboxylation using CO₂. However, the first and second steps could be replaced by a favored concerted one-step mechanism without forming the iron hydride complex. The rate-limiting step for the whole catalytic cycle is the reductive elimination step, where the energy barrier ΔE is 37.3 kcal/mol in the gas phase and the Gibbs free energy in solvent THF ΔG_sol is 30.3 kcal/mol, computed using the SMD method. The mechanisms to obtain the byproduct β-carboxylic acids are also studied.