title: Hydroxy-Directed Amidation of Carboxylic Acid Esters Using a Tantalum Alkoxide Catalyst.
abstract: We describe herein a new strategy for the chemoselective synthesis of amides by using a metal-catalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis.
authors.affiliation: Molecular Catalyst Research Center, Chubu University , 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tsuji
authors.affiliation: Molecular Catalyst Research Center, Chubu University , 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamamoto