Homologation of aryl ketones to long-chain ketones and aldehydes via C-C bond cleavage

Palladium-Catalyzed C(O)-C Bond Cleavage of Unstrained Ketones Assisted with Aryl Handles: An Approach to Diaryl Ketones

C-C bond cleavage reactions have achieved remarkable progress in molecular deconstruction and skeleton editing. In this study, we describe a palladium-catalyzed synthesis of diaryl ketones through a sequence of α-arylation and aerobic oxidative C-C bond cleavage. This transformation features good functional group compatibility, especially for highly reactive groups, including -OH, NH2, and -CHO. Furthermore, this approach allows for gram-scale synthesis in a low catalyst loading manner. It also streamlines the synthesis of a variety of drugs or their intermediates. Mechanism studies reveal the essential role of utilizing a bulky ligand and the existence of air as the reaction atmosphere.

Ring expansion of 3-hydroxyoxindoles to 4-quinolones via palladium-catalyzed C-C(acyl) bond cleavage

We report herein the construction of 4-quinolones via palladium-catalyzed regioselective β-acyl elimination of 3-hydroxyoxindoles and a subsequent Camps cyclization process. This protocol is highly efficient and various 4-quinolone derivatives are obtained in high yields. The construction of the core skeleton of the 4-quinolone antibiotics demonstrated the synthetic utility of this method.

Palladium-Catalyzed Deuteration of Arylketone Oxime Ethers

We report herein the development of palladium-catalyzed deacylative deuteration of arylketone oxime ethers. This protocol features excellent functional group tolerance, heterocyclic compatibility, and high deuterium incorporation levels. Regioselective deuteration of some biologically important drugs and natural products are showcased via Friedel-Crafts acylation and subsequent deacylative deuteration. Vicinal meta-C-H bond functionalization (including fluorination, arylation, and alkylation) and para-C-H bond deuteration of electro-rich arenes are realized by using the ketone as both directing group and leaving group, which is distinct from aryl halide in conventional dehalogenative deuteration.

Construction of polysubstituted pentafulvenes via palladium-catalyzed deacetylation of enones

Herein, we report an efficient synthetic method for polysubstituted pentafulvenes via palladium-catalyzed deacetylative [2+2+1] annulation of enones with alkynes. Aryl-, alkenyl-, and alkyl-substituted α,β-enones were suitable substrates, affording the pentafulvene products in moderate to good yields. This protocol shows excellent compatibility with sensitive halides, free hydroxyl groups, and heterocycles. One-pot gram-scale synthesis and further applications in the late-stage modification of natural products demonstrate the synthetic utility of this method.

Merging the Norrish type I reaction and transition metal catalysis: photo- and Rh-promoted borylation of C-C σ-bonds of aryl ketones

Synthesis of arylboronates via borylation of C-C σ-bonds of aryl ketones was achieved by the combined use of photoenergy and a Rh catalyst. The cooperative system enables α-cleavage of photoexcited ketones to generate aroyl radicals via the Norrish type I reaction, which are successively decarbonylated and borylated with the rhodium catalyst. This work establishes a new catalytic cycle merging the Norrish type I reaction and Rh catalysis and demonstrates the new synthetic utility of aryl ketones as aryl sources for intermolecular arylation reactions.

Construction of C(sp2)-Si Bonds via Ligand-Promoted C-C Bonds Cleavage of Unstrained Ketones

Herein, we report an efficient palladium-catalyzed silylation of aryl and alkenyl ketones via C-C bond cleavage and C-Si bond formation. This protocol features high efficiency and broad substrate scope. Further applications in the late-stage diversification of biologically important molecules demonstrate the synthetic utility of this method.