Visible‐Light‐Enabled Direct Decarboxylative N‐Alkylation. Issue 20 (17th March 2020) - Nguyen, Vu T.
Abstract: The development of efficient and selective C−N bond‐forming reactions from abundant feedstock chemicals remains a central theme in organic chemistry owing to the key roles of amines in synthesis, drug discovery, and materials science. Herein, we present a dual catalytic system for the N‐alkylation of diverse aromatic carbocyclic and heterocyclic amines directly with carboxylic acids, by‐passing their preactivation as redox‐active esters. The reaction, which is enabled by visible‐light‐driven, acridine‐catalyzed decarboxylation, provides access to N‐alkylated secondary and tertiary anilines and N‐heterocycles. Additional examples, including double alkylation, the installation of metabolically robust deuterated methyl groups, and tandem ring formation, further demonstrate the potential of the direct decarboxylative alkylation (DDA) reaction. Abstract : No beating about the bush : (Hetero)aromatic amines underwent decarboxylative N‐alkylation directly with carboxylic acids with a dual copper/acridine photocatalytic system. The directional character of the acridine photocatalysis facilitates the challenging decarboxylation of unactivated carboxylic acids in the presence of more readily oxidizable anilines, thus enabling the use of a wide range of structurally diverse amine and acid substrates (see scheme).