Photoinduced Decarboxylative Radical Phosphinylation

Abstract

Reported herein is an unprecedented protocol for C(sp3)–phosphinylation. With 1 mol % 4CzIPN (1,2,3,5‐tetrakis(carbazol‐9‐yl)‐4,6‐dicyanobenzene) as the catalyst, the visible light‐induced reaction of redox‐active esters of aliphatic carboxylic acids with dimethyl arylphosphonites or diethyl alkylphosphonites at room temperature provides the corresponding decarboxylative phosphinylation products in satisfactory yields. The protocol exhibits broad substrate scope and wide functional group compatibility, enabling the late‐stage modification of complex molecules and rapid synthesis of bioactive phosphinic acids such as glutamine synthetase phosphinothricin and a kynureninase inhibitor. A radical–polar crossover mechanism involving the formation and subsequent oxidation of phosphoranyl radicals followed by nucleophilic demethylation (or deethylation) is proposed.

Facile synthesis of alkylphosphonates from 4-alkyl-1,4-dihydropyridines via photoinduced formal deformylative phosphonylation

“…However, there have been no reports to date on deformylative C(sp 3 )–P(O) bond formations. In continuation of our interest in radical phosphorylation, 6,9,10,19 we herein report the photocatalyzed deformylative phosphonylation of alkyl aldehydes via DHPs. The protocol features metal-free and redox-neutral conditions, high reaction efficiency and broad substrate diversity.…”

Catalyst-Free, Zn-Mediated Decarboxylative Coupling of Chlorostibines to Access Alkylstibines with Stable C(sp3)–Sb Bonds

“…In recent years, numerous reports on decarboxylative C­(sp 3 )–C cross-coupling from NHP esters have emerged . Pioneering work on decarboxylative cross-coupling toward C­(sp 3 )–N­(P), C­(sp 3 )–O­(S, Se, Te), and C­(sp 3 )–F­(Cl, Br, I) bonds has been well established (Scheme a). Compared with these advancements, the construction of a C­(sp 3 )–metal bond from decarboxylative coupling of aliphatic carboxylic acids or NHP esters has been relatively rare; recently, only three kinds of metals (B, Si, and Ge) have been disclosed with few successful examples (Scheme b).…”