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Dual Gold/Silver Catalysis: 3-Alkynylpyrroles via a Tandem C(sp2)-H Alkynylation/N-Alkynylation
Peng Shen1, Peifeng Li1, Mengyu Liu1
1Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, P. R. China.
Abstract:
A dual gold/silver-catalyzed cascade C(sp2)-H alkynylation/N-alkynylation of enamines with hypervalent iodine(III) reagents for the synthesis of 3-alkynylpyrroles is reported. This cooperative Au/Ag catalytic system enables the one-step construction of multisubstituted pyrrole frameworks under mild conditions. Mechanistic studies allowed the capture of the initially formed Au(I) species and support a pathway involving an alkynyl Au(III) intermediate together with a silver-assisted C-H activation process. The cascade sequence efficiently forges C-C and C-N bonds, providing 3-alkynylpyrroles in good yields with broad functional group tolerance. Gram-scale synthesis and further derivatization of the products highlight the practicality and synthetic utility of this transformation.
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