Copper-Catalyzed Chemodivergent Synthesis of Oxazoles and Imidazolidones by Selective C–O/C–N Cyclization

Abstract

Efficient synthesis of phenylalanine-derived oxazoles and imidazolidones can be achieved by copper-catalyzed reactions that are controlled by directing groups and proceed by selective C−O or C−N coupling. This strategy employs inexpensive commercial copper catalysts and readily available starting materials. It uses a convenient reaction procedure and provides a reliable approach to the versatile and flexible assembly of heterocyclic building blocks.

Late-Stage Diversification of Peptides via Pd-Catalyzed Site-Selective δ-C(sp2)-H Fluorination and Amination

“…However, to the best of our knowledge, the successful demonstration of transition metal-catalyzed site-selective C­(sp 2 )-H fluorination of peptides remains elusive. In continuation of our research interest in the functionalization of amino acids and peptides through transition metal-catalyzed C–H activation, herein, we present a facile strategy for late-stage functionalization of peptides via Pd-catalyzed site-selective δ-C­(sp 2 )-H fluorination and amination of phenylalanine (Phe) residues with the assistance of the picolinamide (PA) directing group (Figure C). Notably, our methodology enables the construction of fluorinated indoline scaffolds within peptides, demonstrating a straightforward approach for late-stage peptide fluorination through Pd-catalyzed C–H activation.…”