ORGN 935 |
| Two complementary catalytic methods are described for the preparation of N- aryl and alkyl benzimidazoles in regiochemical pure forms starting from ortho-halo anilides or anilines. The first method employing Pd2(dba)3 and XPhos or RuPhos permits efficient synthesis of N-aryl benzimidazoles and tolerates a wide range of functional groups. The second method utilizing CuI and trans-N, N'-dimethyl-1,2-cyclohexanediamine allows for the preparation of N-alkyl benzimidazoles in good to excellent yields. Additionally, the substrate scope was expanded for the synthesis of N-aryl benzimidazoles by performing sequential amidation and amination on difunctionalized arenes bearing two ortho-disposed halides or tosylates. |
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Heterocycles and Aromatics
8:00 AM-12:00 PM, Thursday, August 23, 2007 BCEC -- 254 A/B, Oral
Division of Organic Chemistry |