Jun Ying

Direct synthesis of benzylic amines by palladium-catalyzed carbonylative aminohomologation of aryl halides

Benzylic amines are valuable compounds with important applications in areas including pharmaceuticals and agrochemicals. The known procedures for their synthesis are limited by difficulties in functionalizing the parent aminomethyl groups. On the other hand, carbonylation reactions offer a potent method to introduce carbonyl groups and homologate carbon chains. However, carbonylative aminohomologation of aryl halides is challenging due to competing reactions and the need to balance multiple sequential steps. Here we report a palladium-catalyzed carbonylative aminohomologation reaction for the direct aminomethylation of aryl halides. The reaction proceeds via a tandem palladium-catalyzed formylation, followed by imine formation and formic acid-mediated reduction. Useful functional groups including chloride, bromide, ester, ketone, nitro, and cyano are compatible with this reaction. Both aryl iodides and bromides are suitable substrates and a wide range of synthetically useful amines are efficiently obtained in moderate to excellent yields.Palladium can catalyse both the reductive carbonylation of aryl halides to aldehydes, and the reductive amination of benzaldehydes with amines. Here the authors describe a tandem reductive carbonylation/reductive amination using carbon monoxide as the carbonyl source, constituting aminomethylation of aryl halides

Nickel-Catalyzed Carbonylative Synthesis of Functionalized Alkyl Iodides

Summary Functionalized alkyl iodides are important compounds in organic chemistry and biology. In this communication, we developed an interesting nickel-catalyzed carbonylative synthesis of functionalized alkyl iodides from aryl iodides and ethers. With Mo(CO)6 as the solid CO source, both cyclic and acyclic ethers were activated, which is also a challenging topic in organic synthesis. Functionalized alkyl iodides were prepared in moderate to excellent yields with outstanding functional group tolerance. Besides the high value of the obtained products, all the atoms from the starting materials were incorporated in the final products and the reaction had high atom efficiency as well.

Palladium-Catalyzed Carbonylative Synthesis of α,β-Unsaturated Amides from Styrenes and Nitroarenes

A procedure on palladium-catalyzed selective aminocarbonylation of styrenes with nitroarenes for the synthesis of α,β-unsaturated amides has been developed. A range of substituted α,β-unsaturated amides were synthesized in moderate to good yields. Interestingly, nitroarenes act as both a nitrogen source and oxidant, and Mo(CO)6 acts as a solid CO source and reductant in this catalytic system.

Pd/C-catalyzed reductive carbonylation of nitroaromatics for the synthesis of unsymmetrical ureas: one-step synthesis of neburon

A Pd/C catalyzed reductive carbonylation of nitroarenes for the synthesis of unsymmetrical ureas has been developed. Using inexpensive and stable nitroarenes as the substrates, a series of unsymmetrical ureas were produced in moderate to good yields. A range of functional groups including thioethers, halides and vinyl were compatible with this reaction. As a heterogeneous catalyst, Pd/C was recycled and reused four times without losing activity. Notably, urea-based herbicide neburon was prepared in 64% yield under our standard conditions.

Nickel-Catalyzed Molybdenum-Promoted Carbonylative Synthesis of Benzophenones

A nickel-catalyzed molybdenum-promoted carbonylative coupling reaction for the synthesis of benzophenones from aryl iodides has been developed. Various substituted diaryl ketones were synthesized in moderate to excellent yields under CO-gas-free conditions. A synergetic effect of both nickel and molybdenum has been observed, which is also responsible for the success of this transformation.

Palladium-Catalyzed Carbonylative Synthesis of N-Acetyl Benzoxazinones

A palladium‐catalyzed intramolecular carbonylation reaction for the synthesis of N‐acetyl benzoxazinones has been achieved for the first time. To avoid the using of toxic and flammable CO gas, formic acid was utilized as the CO source here. This carbonylative process is conducted under mild reaction conditions with high reaction efficiency. A variety of the desired N‐acetyl benzoxazinone products were obtained in moderate to excellent yields with very good functional group compatibility. The presents of acid anhydride holds two roles here: formic acid activator and acyl source.