American Chemical Society
jo3c01757_si_001.pdf (5.3 MB)

Organo-photoredox-Catalyzed Selective Mono- and Bis-C–H Alkylation of Electron-Rich (Hetero)Arenes

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journal contribution
posted on 2023-10-12, 12:34 authored by Shyamal Pramanik, Partha Pratim Mondal, Soumitra Maity
Herein, we disclose a simple strategy for the C–H alkylation of electron-rich (hetero)­arenes with alkyl bromides employing visible-light-mediated organo-photocatalytic SET processes. The generality of this method has been evidenced by the inclusion of a variety of alkyl radicals (α-alkyl-carbonyl, benzyl, cyanomethyl) as well as diverse biologically active electron-rich arenes and (hetero)­arenes under mild conditions. The extent of alkylation with alkyl bromides was found to be controlled by introducing Zn­(OAc)2 as a bromide scavenger, ensuring the blocking of potential bromo-arene byproduct formation under photoredox conditions. In addition, a sequential C–H alkylation strategy for selective bis-alkylation has also been developed via chronological incorporation of different alkyl radical precursors in one pot quite efficiently.