Redox-economical radical generation from organoborates and carboxylic acids by organic photoredox catalysis

Abstract

Redox-economical radical reactions by organic photoredox catalysis.

Fragment Coupling and the Construction of Quaternary Carbons Using Tertiary Radicals Generated Fromtert-AlkylN-Phthalimidoyl Oxalates By Visible-Light Photocatalysis

“…Recent total synthesis endeavors in our laboratories have suggested the potentially broad utility of both trialkyl-tertiary cuprates and nucleophilic carbon radicals in such constructions. 1,2,3 Tertiary carbon radicals are often generated from halide precursors. However, the synthesis of structurally elaborate tertiary halides can be complicated by competing elimination and rearrangement reactions.…”

“…1c To extend this approach to other readily available precursors, we recently described the utility of N -phthalimidoyl oxalate derivatives of tertiary alcohols for generating tertiary radicals using visible-light photocatalysis. 3b …”

“…Since our recent studies of photoredox-catalyzed generation of tertiary radicals and their use in fragment coupling reactions, 1b,c,3b several other research programs contributed important new methods for accessing tertiary carbon radical intermediates. Baran described the reaction of substituted alkenes with Fe(acac) 3 /PhSiH 3 to generate secondary and tertiary radicals and their use in both intramolecular and bimolecular C–C bond-formation.…”

Visible‐Light Photocatalysis as an Enabling Tool for the Functionalization of Unactivated C(sp3)‐Substrates

“…[47] In this Scheme 25. Metal-and oxidant-free cyanation using alkyltrifluoroborates and suggested mechanism.…”

“…Later, Akida and co-workers demonstrated that this transformation can also be accomplished with the organic photocatalyst 21 (see Scheme 10B). [47] Scheme 12. Ir-catalyzed radical decarboxylative Giese-type addition with alkyl carboxylic acids and suggested mechanism.…”