Wanfang Li

Palladium-Catalyzed Carbonylative Synthesis of Benzoxazinones from N-(o-Bromoaryl)amides Using Paraformaldehyde as the Carbonyl Source

Carbonylation reactions have been widely used in organic synthesis. However, the manipulation of toxic and pressurized carbon monoxide limited their applications in organic laboratories. The search for alternative carbonyl sources as an important method for carbonylative organic synthesis is spreading. Herein, a series of substituted benzoxazinones were synthesized from N-(o-bromoaryl)amides by palladium-catalyzed carbonylation with paraformaldehyde as the carbonyl source, which is inexpensive, stable, and easy to use. Notably, this is the first example of using paraformaldehyde as the CO source in palladium-catalyzed carbonylative synthesis of heterocycles.

A Novel Domino Synthesis of Quinazolinediones by Palladium-Catalyzed Double Carbonylation

Combining commercially available bromoanilines and bromobenzonitriles in a novel double carbonylation process allows for a straightforward synthesis of isoindolo[1,2-b]quinazoline-10,12-diones. At least five different CC and/or CN bonds are selectively formed in this 3-component reaction, which likely proceeds through sequential carbonylation-cyclization-isomerisation-carbonylation steps. Notably, two molecules of CO are inserted in this highly efficient palladium-catalyzed process.

Palladium‐Catalyzed Aminocarbonylation of N‐Chloroamines with Boronic Acids

Aryl (pseudo)halide-based (C-X) carbonylation reactions have been extensively studied during the past few decades. From both academic and synthetic points of view, the carbonylative transformation of N-X bonds represents an interesting and attractive area of investigation. In light of this, the first carbonylative cross-coupling between N-chloroamines and organoboronic acids has been developed. This new type of aminocarbonylation proceeds at mild temperatures (45-55 °C) with 2 mol % Pd/C (10 wt %) as the ligand-free catalyst. Not only arylboronic acids, but also alkenyl- and alkylboronic acids can be applied as the substrates and bromide and iodide substituents in the substrates are well tolerated. Initial mechanistic investigations have also been performed.

A Practical and General Base‐Catalyzed Carbonylation of Amines for the Synthesis of N‐Formamides

A highly practical and general base-catalyzed carbonylation of amines to the corresponding N-formamides has been realized. Cheap inorganic bases, including Group IA and IIA metal hydroxides, alkoxides, carbonates, and phosphates, were effective catalysts for the transformation. In the presence of 10-40 mol % of KOH or K2 CO3 , various amines were converted into the corresponding N-formamides in good-to-excellent yields using CO as the formylation reagents.

Transition metal-free methylation of amines with formaldehyde as the reductant and methyl source

A simple transition metal-free procedure using formal dehyde for the N,N-dimethylation and N-methylation of primary and secondary anilines is reported. The reaction showed limitations on sterically hindered and electron-withdrawing anilines, but is successful on amines with electron-donating substituents. Formaldehyde acts as both the reducing agent and the carbon source in the reaction.