C2-Selective Branched Alkylation of Benzimidazoles by Rhodium(I)-Catalyzed C-H Activation
Gaël Tran1, Danielle Confair1, Kevin D Hesp2
1Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States.
Abstract:
Herein, we report a Rh(I)/bisphosphine/K3PO4 catalytic system allowing for the first time the selective branched C-H alkylation of benzimidazoles with Michael acceptors. Branched alkylation with N,N-dimethyl acrylamide was successfully applied to the alkylation of a broad range of benzimidazoles incorporating a variety of N-substituents and with both electron-rich and -poor functionality displayed at different sites of the arene. Moreover, the introduction of a quaternary carbon was achieved by alkylation with ethyl methacrylate. The method was also shown to be applicable to the C2-selective branched alkylation of azabenzimidazoles.
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