Tunable Unsymmetrical Chiral N-Heterocyclic Carbene Ligands for Highly Diastereo-and Enantioselective Copper-Catalyzed Tandem Borylative Cyclization:Ligand Controlled Diastereoselectivity Reversal  

作　　者：Jiahong Han Yan-Mei He Yixiao Pan Faju Li Dongyu Li Wei Hao Qing-Hua Fan 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,CAS Key Laboratory of Molecular Recognition and Function,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190 [2]University of Chinese Academy of Sciences,Beijing 100049

出　　处：《CCS Chemistry》2023年第9期2088-2100,共13页中国化学会会刊（英文）

基　　金：the National Key R&D Program of China(grant no.2021YFA1500200);the National Natural Science Foundation of China(grant nos.92056108 and 92256303)for financial support.

摘　　要：A distinct class of C1-symmetric N-heterocyclic carbene(NHC)ligands possessing a chiral fused tetrahydroquinoline ring and a chiral N-arylmethyl group was designed and synthesized via an asymmetric catalytic synthesis strategy.Their copper(I)complexes were successfully applied to asymmetric borylation/cyclization tandem reactions,providing facile access to a broad range of chiral borylated 2,3-trans-3,4-cis-trisubstituted tetrahydroquinolines,which are synthetically important and otherwise difficult to access,in high yields with excellent enantioselectivities and diastereoselectivities.The single-crystal X-ray diffraction analyses of the Cu(I)complexes of L3 and L6 indicate that a crowded chiral pocket around the Cu(I)-metal center is created that is beneficial for the chiral induction in this asymmetric tandemreaction.In addition,chiral all-cis 2,3,4-trisubstituted tetrahydroquinolines were also prepared by using a less bulky C2-symmetric chiral NHC ligand.A plausible catalytic cycle and transition states were proposed to account for the observed diastereoselectivity reversal.

关 键 词：N-heterocycliccarbenes asymmetricca-talysis boron copper tandemreaction tetrahy-droquinolines 

分 类 号：O621.251[理学—有机化学]