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Switchable photocatalysis for the chemodivergent benzylation of 4-cyanopyridines.

ABSTRACT: We report a photocatalytic strategy for the chemodivergent radical benzylation of 4-cyanopyridines. The chemistry uses a single photoredox catalyst to generate benzyl radicals upon N-F bond activation of 2-alkyl N-fluorobenzamides. The judicious choice of different photocatalyst quenchers allowed us to select at will between mechanistically divergent processes. The two reaction manifolds, an ipso-substitution path proceeding via radical coupling and a Minisci-type addition, enabled selective access to regioisomeric C4 or C2 benzylated pyridines, respectively. Mechanistic investigations shed light on the origin of the chemoselectivity switch.

SUBMITTER: Georgiou E

PROVIDER: S-EPMC9278488 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature

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Switchable photocatalysis for the chemodivergent benzylation of 4-cyanopyridines.

Georgiou Eleni E Spinnato Davide D Chen Kang K Melchiorre Paolo P Muñiz Kilian K

Chemical science 20220607 27

We report a photocatalytic strategy for the chemodivergent radical benzylation of 4-cyanopyridines. The chemistry uses a single photoredox catalyst to generate benzyl radicals upon N-F bond activation of 2-alkyl N-fluorobenzamides. The judicious choice of different photocatalyst quenchers allowed us to select at will between mechanistically divergent processes. The two reaction manifolds, an ipso-substitution path proceeding via radical coupling and a Minisci-type addition, ...[more]

PMID: 35919417

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