Abstract
<jats:p>Amines are ubiquitous in natural products and pharmaceuticals and represent abundant feedstocks for chemical synthesis. Although traditionally exploited for C–N bond formation, they are increasingly being repurposed as carbonbased coupling partners. Bimolecular homolytic substitution (SH2) provides a complementary approach to C(sp3)–C(sp3) bond formation by enabling the selective union of carbon-centred radicals and is particularly well suited to constructing sterically congested quaternary centres. Here, we report an iron-catalysed deaminative alkene hydrobenzylation, allowing two abundant feedstock classes, benzylamines, employed as their readily accessible redox-active pyridinium salts, and alkenes, to engage in forging sterically congested C(sp3)–C(sp3) bonds. Mechanistic studies support a radical-sorting pathway in which a single iron–porphyrin catalyst mediates reversible MHAT, reduction of the pyridinium salt, benzyl-radical capture, and C–C bond formation through SH2. The transformation accommodates a broad range of alkenes, including α-heteroatom-substituted substrates bearing N, O, S, B, or Si substituents, and furnishes diverse hydrobenzylation products, including all-carbon quaternary centres, in generally moderate to high yields. Access to medicinally relevant scaffolds, together with the late-stage functionalisation of bioactive natural products and pharmaceuticals, highlights the utility of this method for rapidly generating structurally complex, C(sp3)-rich molecules.</jats:p>