Synthesis and application of a dual chiral [2.2]paracyclophane-based N-heterocyclic carbene in enantioselective β-boration of acyclic enones.
An enantioselective conjugate addition of boron to α,β-unsaturated ketones catalysed by either a N-heterocyclic carbene or a copper-carbene complex generated in situ from a new chiral bicyclic triazolium based on [2.2]paracyclophane is presented. The dual chiral carbene-copper catalyst has significant advantages over its carbene counterpart as an organocatalyst in asymmetric β-boration of acyclic enones, giving a variety of chiral β-boryl ketones in good yields and enantioselectivities. This is a successful example of employing the same N-heterocyclic carbene in one catalytic reaction as both an organocatalyst and a ligand for transition metal catalysis.
Department of Chemistry, Shandong University, Shanda South Road No. 27, Jinan 250100, China. ydma@sdu.edu.cn.
Lei
L
Wang
Department of Chemistry, Shandong University, Shanda South Road No. 27, Jinan 250100, China. ydma@sdu.edu.cn.
Zhen
Z
Chen
School of Pharmaceutical Sciences, West Wenhua Road No. 44, Jinan 250012, China. chunsong@sdu.edu.cn.
Manyuan
M
Ma
School of Chemistry and Chemical Engineering, Liaocheng University, Hunan Road No. 1, Liaocheng 252000, China.
Wenzeng
W
Duan
School of Pharmaceutical Sciences, West Wenhua Road No. 44, Jinan 250012, China. chunsong@sdu.edu.cn.
Chun
C
Song
Department of Chemistry, Shandong University, Shanda South Road No. 27, Jinan 250100, China. ydma@sdu.edu.cn.
Yudao
Y
Ma
D001895:Boron / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D011083:Polycyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism
D001896:Boron Compounds; D006571:Heterocyclic Compounds; D007659:Ketones; D011083:Polycyclic Compounds; C515344:(2.2)paracyclophane; C030011:carbene; D003300:Copper; D001895:Boron; D008697:Methane