Synthesis of Azomethines from α‐Oxocarboxylates, Amines and Aryl Bromides via One‐Pot Three‐Component Decarboxylative Coupling

Abstract

A bimetallic palladium/copper catalyst system allows the highly modular synthesis of azomethines via the decarboxylative coupling of aryl halides and a-iminocarboxylates, generated in situ from potassium a-oxocarboxylates and primary amines. The reaction proceeds already at 100 8C, a new record for redox-neutral decarboxylative crosscoupling reactions.

Synergistic Pd/Cu Catalysis in Organic Synthesis

“…Subsequently, Gooβen and co‐workers developed a bimetallic Pd/Cu catalyst system for the synthesis of azomethines from amines, aryl bromides, and α‐oxocarboxylates by a one‐pot three‐component decarboxylative cross‐coupling (Scheme ) …”

Synthesis of Aryl Ethers from Benzoates through Carboxylate‐Directed CH‐Activating Alkoxylation with Concomitant Protodecarboxylation

“…Copper-based systems have been used for similar transformations, [11] including oxygen atom transfer [12] or catalytic acetoxylation reactions, [13] but to the best of our knowledge, no copper-catalyzed C À H activating alkoxylations of arenes have been reported to date. [14] In our studies of decarboxylative coupling reactions, [15,16] we recently disclosed a decarboxylative etherification in which a CÀO bond is formed at the original position of the carboxylate group of benzoates. [14] In our studies of decarboxylative coupling reactions, [15,16] we recently disclosed a decarboxylative etherification in which a CÀO bond is formed at the original position of the carboxylate group of benzoates.…”

“…However, the possibility of directed copper-mediated aryl ether formation is supported by two experimental findings: Yu et al observed the coupling of 2-phenylpyridine with 4-cyanophenol, [13a] and Ribas and Stahl found that methoxylation of a benzene ring within a macrocyclic ligand scaffold takes place in the presence of copper. [14] In our studies of decarboxylative coupling reactions, [15,16] we recently disclosed a decarboxylative etherification in which a CÀO bond is formed at the original position of the carboxylate group of benzoates. [17] For a broad range of substrate combinations, the decarboxylative alkoxylation was found to proceed regiospecifically at the ipso position.…”

Copper‐Catalyzed Double Decarboxylative Coupling Reactions of Alkynyl Carboxylic Acid and Glyoxylic Acid: Synthesis of Propargyl Amines and Imidazopyridines

“…The glyoxylic acid can undergo a reaction with the amine to give aldehyde A and amino alcohol B through a decarboxylation process. The resulting product B then can afford iminium ion C or imidoyl copper complex D in the presence of copper. Upon treatment with alkynyl copper complex E , which can be formed by the decarboxylation of an alkynyl carboxylic acid, C or D can then provide the desired propargyl amine.…”