Palladium-Catalyzed C(sp3)-H Nitrooxylation of Aliphatic Carboxamides with Practical Oxidants

J Org Chem. 2024 Feb 2;89(3):1417-1424. doi: 10.1021/acs.joc.3c01911. Epub 2024 Jan 18.

Abstract

Here we report the palladium-catalyzed β-C(sp3)-H nitrooxylation of aliphatic carboxamides using a modified quinoline auxiliary. Notably, Al(NO3)3·9H2O was used as a nitrate source as well as a practical oxidant. The 5-chloro-8-aminoquinoline auxiliary was nitrated in situ during the reaction, which may enhance its directing ability and help its removal. The reaction has a broad substrate scope with a variety of aliphatic carboxamides. The multiple substituted auxiliary can be easily removed and recovered. Two C-H-insertion palladacycle intermediates were isolated and characterized to elucidate the mechanism.