Aryl halide (Br, Cl, I) is among the most important compounds in pharmaceutical industry, material science, and agrochemistry, broadly utilized in diverse transformations. Tremendous approaches have been established to prepare this scaffold; however, many of them suffer from atom economy, harsh condition, inability to be scaled up, or cost-unfriendly reagents and catalysts. Inspired by vanadium haloperoxidases herein we presented a biomimetic approach for halogenation (Br, Cl, I) of (hetero)arene catalyzed by tungstate under mild pH in a costefficient and environment-and operation-friendly manner. Broad substrates, diverse functional group tolerance, and good chemo-and regioselectivities were observed, even in late-stage halogenation of complex molecules. Moreover, this approach can be scaled up to over 100 g without time-consuming and costly column purification. Several drugs and key precursors for drugs bearing aryl halides (Br, Cl, I) have been conveniently prepared based on our approach.
Functionalizing
molecules through the selective cleavage of carbon–carbon
bonds is an attractive approach in synthetic chemistry. Despite recent
advances in both transition-metal catalysis and radical chemistry,
the selective cleavage of inert Csp3–Csp3 bonds in hydrocarbon feedstocks remains challenging. Examples reported
in the literature typically involve substrates containing redox functional
groups or highly strained molecules. In this article, we present a
straightforward protocol for the cleavage and functionalization of
Csp3–Csp3 bonds in alkylbenzenes using
photoredox catalysis. Our method employs two distinct bond scission
pathways. For substrates with tertiary benzylic substituents, a carbocation-coupled
electron transfer mechanism is prevalent. For substrates with primary
or secondary benzylic substituents, a triple single-electron oxidation
cascade is applicable. Our strategy offers a practical means of cleaving
inert Csp3–Csp3 bonds in molecules without
any heteroatoms, resulting in primary, secondary, tertiary, and benzylic
radical species.
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