RESUMO
We herein document the first example of a reliable copper-catalyzed Huisgen 1,3-dipolar cycloaddition under oxidative conditions. The combined use of two polymer-supported reagents (polystyrene-1,5,7-triazabicyclo[4,4,0]dec-5-ene/Cu and polystyrene-2-iodoxybenzamide) overcomes the thermodynamic instability of copper(I) species toward oxidation, enabling the reliable Cu-catalyzed Huisgen 1,3-dipolar cycloadditions in the presence of an oxidant agent. This polymer-assisted pathway, not feasible under conventional homogeneous conditions, provides a direct assembly of 4-acyl-1-substituted-1,2,3-triazoles, contributing to expand the reliability and scope of Cu(I)-catalyzed alkyne-azide cycloaddition.
Assuntos
Alcinos/química , Azidas/química , Cobre/química , Poliestirenos/química , Triazóis/síntese química , Catálise , Ciclização , Estrutura Molecular , Oxirredução , Termodinâmica , Triazóis/químicaRESUMO
A convergent and versatile Vilsmeier-Haack-based carbo-annulation strategy that exhibits an unusually elevated bond-forming efficiency has been developed. By virtue of its innovative approach, structure economy and simple execution conditions the methodology reported here constitutes a very attractive protocol that enables the rapid assembly of structurally diverse quinazoline chemotypes.