Yang Yiying, Liu Yanhong, Zhu Rongxiu, Liu Chengbu, Zhang Dongju
Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , P. R. China.
J Org Chem. 2019 Aug 2;84(15):9705-9713. doi: 10.1021/acs.joc.9b01441. Epub 2019 Jul 11.
This work presents a DFT study on the mechanism and origin of catalyst-controlled divergent reactivity in the synthesis of benzo-heterocycles from -alkynylbenzamides by Au(I)/Pt(IV) catalysis. The results indicate that the transformations proceed via a nucleophilic cyclization process. In the Au(I) catalysis, the preferred -attack mode mainly originates from the symmetry match in the dominant bond-forming interaction between the lone-pair orbital of carbonyl-O and the in-plane alkyne π* orbital, and the electronic property of the ligand controls the -5--/-6-- selectivity. The preference for the -attack mode in Pt(IV) catalysis is attributed to the stronger coordinate capability of carbonyl-O than amino-N in the substrate to PtCl, and the regioselective -6-- or -5-- cyclization depends on the stronger electrostatic interaction between the amino-N and alkynyl-C atoms. The theoretical results provide a fundamental understanding of why and how gold and platinum complexes catalyze the cyclization of -alkynylbenzamides with different chemo- and regioselectivities.
本工作展示了一项关于通过金（I）/铂（IV）催化从α-炔基苯甲酰胺合成苯并杂环时催化剂控制的发散反应性的机理和起源的密度泛函理论（DFT）研究。结果表明，这些转化过程通过亲核环化过程进行。在金（I）催化中，优先的α-进攻模式主要源于羰基-O的孤对轨道与面内炔烃π*轨道之间主要成键相互作用中的对称性匹配，并且配体的电子性质控制了-5-/-6-选择性。铂（IV）催化中对α-进攻模式的偏好归因于底物中羰基-O比氨基-N对PtCl具有更强的配位能力，并且区域选择性的-6-或-5-环化取决于氨基-N与炔基-C原子之间更强的静电相互作用。理论结果为金和铂配合物为何以及如何以不同的化学和区域选择性催化α-炔基苯甲酰胺的环化提供了基本理解。
