Synergistic Visible-Light Photoredox/Nickel-Catalyzed Synthesis of Aliphatic Ketones via N–C Cleavage of Imides

Abstract

An electrophilic, imide-based, visible-light-promoted photoredox/Ni-catalyzed cross-coupling reaction for the synthesis of aliphatic ketones has been developed. This protocol proceeds through N–C(O) bond activation, made possible through the lower activation energy for metal insertion into this bond due to delocalization of the lone pair of electrons on the nitrogen by electron-withdrawing groups. The operationally simple and mild cross-coupling reaction is performed at ambient temperature and exhibits tolerance for a variety of functional groups.

Synergistic Photoredox/Transition‐Metal Catalysis for Carbon–Carbon Bond Formation Reactions

“…The same year, Molander and co‐workers reported two more examples for this photoredox/Ni catalytic paradigm. Indeed, starting from acyl succinimide derivatives 383 and in the presence of secondary alkyltrifluoroborates 384 , the cross‐coupling reaction led to the synthesis of aliphatic ketones 385 via a C–N bond activation by the Nickel (Scheme ) . In fact, the latter can easily insert itself into the C–N bond (between the acyl and succinimide moiety) because of the delocalization of the nitrogen lone pair of electrons which lower the activation energy necessary for its insertion.…”

Water Phase, Room Temperature, Ligand‐Free Suzuki–Miyaura Cross‐Coupling: A Green Gateway to Aryl Ketones by C–N Bond Cleavage

“…Collectively, palladium was the most active catalyst in this transformation (Table , entries 2–3). Encouraged by the Ni catalyst acyl transfer coupling reaction, several nickel catalysts, such as Ni(COD) 2 , NiCl 2 , were investigated. After several experiments, we found these nickel catalysts did not show compatibility with this reaction (Table , entries 4–5).…”

“…1‐(3‐Methylbenzoyl)pyrrolidine‐2,5‐dione (1c): Following general procedure, 1c was purified by recrystallization to afford a white solid (0.69 g, 63.5 %). 1 H NMR (400 MHz, CDCl 3 ) δ = 7.65 (s, 1H), 7.60 (d, J = 7.7 Hz, 1H), 7.45 (d, J = 7.6 Hz, 1H), 7.36 (t, J = 7.7 Hz, 1H), 2.91 (s, 4H), 2.39 (s, 3H).…”

“…Phenyl( m ‐tolyl)methanone (3c): Following general procedure for Suzuki–Miyaura coupling of amides, 3c was purified by column chromatography (petroleum ether/EtOAc = 50:1) to afford a colorless oily liquid (44.7 mg, 76 %). 1 H NMR (600 MHz, CDCl 3 ) δ = 7.71 (dd, J = 8.3, 1.2 Hz, 2H), 7.54 (s, 1H), 7.51–7.47 (m, 2H), 7.40–7.36 (m, 2H), 7.30 (d, J = 7.5 Hz, 1H), 7.26 (t, J = 7.5 Hz, 1H), 2.32 (s, 3H).…”

Alkyl‐C‐C‐Bindungsbildung durch Nickel/Photoredox‐Kreuzkupplung

“…[74] Aufd ieser Grundlage wurde die duale Ni/ Photoredox-Katalyse zur Kupplung zahlreicher Acyl-Elektrophile mit Alkylradikalvorstufen eingesetzt. Als Beleg für den modularen Aufbau des Katalysesystems wurden mehrere Klassen von sowohl Acyl-Elektrophilen (Acylchloriden, [75] Acylimiden, [76] Anhydriden, [77] Isocyanaten [78] und Thioestern [77d] )a ls auch Radikalvorstufen in der Reaktion verwendet. Ein selektiver Acyltransferm it gemischten Anhydriden kann beim Vorhandensein von zwei C(sp 2 )-O-Bindungen problematisch sein, da sie von dem Ni-Katalysator unterschieden werden müssen.…”