RESUMEN
Alkyne is a useful functionality incorporated in proteins for site-selective bioconjugation reactions. Although effective bioconjugation reactions such as copper(I)-catalyzed and/or copper-free 1,3-dipolar cycloadditions of alkynes and azides are the most common approaches, the development of new alkyne-based bioconjugation reactions is still an ongoing interest in chemical biology. In this work, a new approach has been developed for selective modification of alkyne-linked peptides and proteins through the formation of arylacetylenes by a cross-coupling reaction of 6-membered ring cyclometalated gold(III) (C^N) complexes (HC^N = 2-arylpyridines) with terminal alkynes. Screening of the reaction conditions with a series of cyclometalated gold(III) complexes with phenylacetylene gave an excellent yield (up to 82%) by conducting the reaction in slightly alkaline aqueous conditions. The reaction scope was expanded to various alkynes, including alkyne-linked peptides to achieve up to >99% conversion. Using fluorescent dansyl (1l) and BODIPY (1m)-linked gold(III) complexes, alkyne-linked lysozyme has been selectively modified.
Asunto(s)
Oro/química , Compuestos Organometálicos/síntesis química , Péptidos/química , Proteínas/química , Alquinos/química , Catálisis , Reacción de Cicloadición , Estructura Molecular , Compuestos Organometálicos/químicaRESUMEN
Unprecedented stable BINOL/gold(III) complexes, adopting a novel C,O-chelation mode, were synthesized by a modular approach through combination of 1,1'-binaphthalene-2,2'-diols (BINOLs) and cyclometalated gold(III) dichloride complexes [(C^N)AuCl2 ]. X-ray crystallographic analysis revealed that the bidentate BINOL ligands tautomerized and bonded to the AuIII atom through C,O-chelation to form a five-membered ring instead of the conventional O,O'-chelation giving a seven-membered ring. These gold(III) complexes catalyzed acetalization/cycloisomerization and carboalkoxylation of ortho-alkynylbenzaldehydes with trialkyl orthoformates.
RESUMEN
Modular assembly of cyclometalated gold(III) complexes by choosing appropriate bidentate C,N-donor ligands and ancillary ligands for chemoselective cysteine modification of peptides and proteins via C-S bond-forming reductive elimination has been achieved.
Asunto(s)
Cisteína/química , Compuestos Orgánicos de Oro/química , Péptidos/química , Albúmina Sérica Bovina/química , Albúmina Sérica/química , Secuencia de Aminoácidos , Animales , Bovinos , Humanos , Ligandos , Modelos Moleculares , Datos de Secuencia Molecular , Oxidación-ReducciónRESUMEN
Stable bis-cyclometallated gold(III) complexes were developed as efficient catalysts for organic transformation reactions by using two strategies: (1) construction of distorted square planar gold(III) complexes and (2) dual catalysis by gold(III) complexes and silver salts.