102705-79-3Relevant academic research and scientific papers
Sustainable Micellar Gold Catalysis - Poly(2-oxazolines) as Versatile Amphiphiles
Lempke, Linda,Ernst, Andrea,Kahl, Fabian,Weberskirch, Ralf,Krause, Norbert
supporting information, p. 1491 - 1499 (2016/05/19)
The application of five polymer amphiphiles in the gold-catalyzed allene cycloisomerizations under aqueous micellar conditions is described. The polymers were prepared by ring-opening cationic polymerization based on poly(2-methyl-2-oxazoline) as hydrophilic segment and different hydrocarbon- or fluorocarbon-based hydrophobic segments. The catalytic activity in the gold-catalyzed allene cyclization is strongly dependent on the type of gold precursor, the salt concentration in the bulk aqueous medium, and the concentration of the polymeric amphiphile. Best results were obtained with 2 mol% of gold(III) bromide, 1 mM of amphiphile and 5 M sodium chloride, affording over 80% yield for different heterocyclic products. The catalyst system is also suitable for the dehydrative cyclization of acetylenic diols to furans. Moreover, successful catalyst recycling was demonstrated in three consecutive runs when using optimized extraction conditions.
Leveraging the micellar effect: Gold-catalyzed dehydrative cyclizations in water at room temperature
Minkler, Stefan R. K.,Isley, Nicholas A.,Lippincott, Daniel J.,Krause, Norbert,Lipshutz, Bruce H.
supporting information, p. 724 - 726 (2014/03/21)
The first examples of gold-catalyzed cyclizations of diols and triols to the corresponding hetero- or spirocycles in an aqueous medium are presented. These reactions take place within nanomicelles, where the hydrophobic effect is operating, thereby driving the dehydrations, notwithstanding the surrounding water. By the addition of simple salts such as sodium chloride, reaction times and catalyst loadings can be significantly decreased.
