Luo Xiaoling, Bai Ruopeng, Liu Song, Shan Chunhui, Chen Changguo, Lan Yu
School of Chemistry and Chemical Engineering, Chongqing University , Chongqing 400030, People's Republic of China.
College of Chemistry and Molecular Sciences, Wuhan University , Wuhan, Hubei 430072, People's Republic of China.
J Org Chem. 2016 Mar 18;81(6):2320-6. doi: 10.1021/acs.joc.5b02828. Epub 2016 Mar 8.
Metal-catalyzed transfer hydroformylation is an important way of cleaving C-C bonds and constructing new double bonds. The newly reported density functional theory (DFT) method, M11-L, has been used to clarify the mechanism of the rhodium-catalyzed transfer hydroformylation reported by Dong et al. DFT calculations depict a deformylation and formylation reaction pathway. The deformylation step involves an oxidative addition to the formyl C-H bond, deprotonation with a counterion, decarbonylation, and β-hydride elimination. After olefin exchange, the formylation step takes place via olefin insertion into the Rh-H bond, carbonyl insertion, and a final protonation with the conjugate acid of the counterion. Theoretical calculations indicate that the alkalinity of the counterion is important for this reaction because both deprotonation and protonation occur during the catalytic cycle. A theoretical study into the formyl acceptor shows that the driving force of the reaction is correlated with the stability of the unsaturated bond in the acceptor. Our computational results suggest that alkynes or ring-strained olefins could be used as formyl acceptors in this reaction.
金属催化的转移氢甲酰化反应是一种断裂碳 - 碳键并构建新双键的重要方法。新报道的密度泛函理论（DFT）方法M11 - L已被用于阐明董等人报道的铑催化转移氢甲酰化反应的机理。DFT计算描绘了一个脱甲酰化和甲酰化反应途径。脱甲酰化步骤包括对甲酰基C - H键的氧化加成、与抗衡离子的去质子化、脱羰基以及β - 氢消除。烯烃交换后，甲酰化步骤通过烯烃插入Rh - H键、羰基插入以及最终与抗衡离子的共轭酸进行质子化而发生。理论计算表明，抗衡离子的碱度对该反应很重要，因为在催化循环中会发生去质子化和质子化。对甲酰基受体的理论研究表明，反应的驱动力与受体中不饱和键的稳定性相关。我们的计算结果表明，炔烃或环张力烯烃可作为该反应中的甲酰基受体。
