Synthesis of Chiral β-Lactams by Pd-Catalyzed Enantioselective Amidation of Methylene C(sp3)-H Bonds Enabled by a 2-Pyridylisopropyl Auxiliary  

作　　者：Ye-Qiang Han Tao Zhou 

机构地区：[1]Department of Chemistry,Zhejiang University,Hangzhou,Zhejiang 310027,China

出　　处：《Chinese Journal of Chemistry》2020年第5期527-528,共2页中国化学（英文版）

摘　　要：In recent years,enantioselective C-H functionalization reactions have emerged as an efficient means to construct complicated chiral molecules.Compared to many precedents on the asymmetric functionalization of aryl C-H bonds,enantioselective functionalization of unbiased methylene C(sp3)-H bonds of linear systems via metal insertion is still very challenging for two main reasons(Scheme 1a).[1]First,it is more difficult to differentiate two enantiotopic protons residing on a single carbon center.Second,unbiased methylene C(sp3)-H bonds are less reactive than those of primary methyl and activated by specific electronic or inductive effects,such as C-H bonds adjacent to N-heteroatom,benzylic position or on conformationally rigid cyclic systems.The major breakthrough was first achieved by the Yu group in 2016(Scheme 1b).They developed a Pd(Ⅱ)-catalyzed arylation of unbiased methylene C(sp3)-H bonds in high enantioselectivity by taking advantage of weakly coordinating monodentate DG with a bidentate acetyl-protected aminoethyl quinolone ligand(up to 96%ee).

关 键 词：bonds breakthrough weakly 

分 类 号：O62[理学—有机化学]