Aquacatalytic A³ Coupling with Silica-Supported CuCl

Significance

The three-component coupling of aldehydes, alkynes, and amines (the so-called A³ coupling) was performed in water with a silica gel supported copper catalyst to give the corresponding propargylamines. Thus, for example, butanal, phenylacetylene, and piperidine were coupled in water at 100 °C in the presence of 0.05 mol% Cu from silica-supported CuCl for 8 hours to give 98% yield of the propargylamine. 20 Examples of A³ combination were reported (60-98% yield) to exhibit the generality of the present catalytic system.