Synthesis of Planar Chiral [2.2]Paracyclophanyl Imidazo[1,5-a]pyridinium Salts for the Rhodium-Catalyzed Asymmetric Arylation |
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Authors: | Dengxia Wang Fuyan He Wenzeng Duan Lei Zhao Chun Song |
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Institution: | Department of Chemistry , Shandong University , Jinan , Shandong , China |
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Abstract: | Abstract Several novel flexibility-restricted imidazo1,5-a]pyridinium triflates (abbreviated as imidazolium salts) were synthesized from (4S p,13R p)-(?)-4-amino-13-bromo2.2]paracyclophane and pyridylaldehyde. These imidazolium salts can be used as nitrogen-containing heterocyclic carbene precursors in asymmetric catalysis and here they are applied in the Rh-catalyzed asymmetric 1,2-addition of arylboronic acids to aldehydes. After optimizing the catalytic situations and testing a series of substrates, moderate enantioselectivity and good yield were obtained. |
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Keywords: | Aldehyde asymmetric arylation N-heterocyclic carbene [2 2]paracyclophane planar chirality |
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