Palladium-Catalyzed Regioselective C–H Functionalization/Annulation Reaction of Amides and Allylbenzenes for the Synthesis of Isoquinolinones and Pyridinones

Abstract

A regioselective C−H functionalization/annulation reaction of N-sulfonyl amides and allylbenzenes through a palladium-catalyzed C(sp 2 )−H allylation/aminopalladation/β−H elimination/isomerization sequence has been reported. Various aryl and alkenyl carboxamides are found to be efficient substrates to construct isoquinolinones and pyridinones in up to 96% yield. Using ambient air as the terminal oxidant is another advantage regarding environmental friendliness and operational simplicity.

Transition‐Metal‐Catalyzed, Chelation‐Assisted C−H Alkenylation and Allylation of Organic Molecules with Unactivated Alkenes

“…Recently, Wang and co‐workers reported a similar kind of transformation with allylbenzenes to synthesize biologically important isoquinolinones and pyridinones (Scheme 60). [56] The reaction mechanism is similar to that of the previous report, metal coordination followed by ortho ‐C−H activation, allylation, and subsequent aminopalladation. Finally, β‐hydride elimination and subsequent isomerization afford the annulated product (Scheme 61).…”

Recent Advances in Alkenyl sp2 C–H and C–F Bond Functionalizations: Scope, Mechanism, and Applications

“…More recently, Wang, Sun, and colleagues elaborated a highly regioselective C−H functionalization/annulation reaction of N-sulfonyl acrylamides with unactivated allylbenzenes (Scheme 199). 342 The reaction occurred in the presence of 10 mol % Pd(TFA) 2 and 20 mol % Cu(OAc) 2 in conjunction with air as the terminal oxidant, which undergoes a C(sp 2 )−H allylation/aminopalladation/β−H elimination/isomerization sequence, leading to an array of highly functionalized pyridinone derivatives in appreciable yields (43−53%).…”

Synergic Palladium Catalysis for Aerobic Oxidative Coupling

“…The cationic Pd either initiates the electrophilic metalation of the aromatic alkene or the intramolecular transcarbopalladation of a C=C bond on the arene, affording a Pd- Xia, Hii and co-worker reported the Pd-catalyzed tandem alkenylation/intramolecular aza-Wacker reaction between Nmethoxybenzamides and styrene derivatives to synthesize isoindolinones (Scheme 23). [89] The replacement of a stoichiometric amount of benzoquinone with Cu(OAc) 2 • 2H 2 O allowed the use of smaller amounts of oxidants.…”

“…Xia, Hii and co‐worker reported the Pd‐catalyzed tandem alkenylation/intramolecular aza ‐Wacker reaction between N ‐methoxybenzamides and styrene derivatives to synthesize isoindolinones (Scheme 23). [89] The replacement of a stoichiometric amount of benzoquinone with Cu(OAc) 2 ⋅ 2H 2 O allowed the use of smaller amounts of oxidants.…”