C–H alkylation of pyridines with olefins catalyzed by imidazolin-2-iminato-ligated rare-earth alkyl complexes  

作　　者：Dawei Li Lichao Ning Qiliang Luo Shiyu Wang Xiaoming Feng Shunxi Dong 

机构地区：[1]Key Laboratory of Green Chemistry&Technology,Ministry of Education,College of Chemistry,Sichuan University,Chengdu 610064,China

出　　处：《Science China Chemistry》2023年第6期1804-1813,共10页中国科学（化学英文版）

基　　金：supported by the National Key R&D Program of China(2022YFA1504301);the National Natural Science Foundation of China(92056107,22271199,92256303,21890723);Sichuan University(2020SCUNL204)。

摘　　要：An array of rare-earth bis(aminobenzyl)complexes supported by imidazolin-2-iminato ligands were synthesized and structurally characterized.These complexes showed high activity towards ortho-Csp^(2)–H alkylation of 2-alkylpyridines and benzylic Csp^(3)–H alkylation of 2,6-dialkylpyridines with alkenes.A wide range of alkyl or aryl substituted olefin substrates are compatible,providing an atom-economical route to linear or branched alkylated pyridine derivatives in moderate to high yields(45 examples,up to 99%yield).The primary study suggested that the asymmetric version of Csp^(3)–H alkylation of 2,4,6-collidine with allylbenzene was feasible with chiral imidazolin-2-iminato-ligated scandium(III)complexes,and good yield with moderate enantioselectivity was obtained(84%yield,84:16 er).Mechanistic investigations including kinetic isotope effect(KIE)experiments and density functional theory(DFT)calculations shed light on the catalytic cycle and the origin of enantiocontrol.

关 键 词：PYRIDINE C-H functionalization RARE-EARTH imidazolin-2-iminato ligand asymmetric catalysis 

分 类 号：O641.4[理学—物理化学] O621.251[理学—化学]