Dispersed Gold Nanoparticles Supported in the Pores of Siliceous Mesocellular Foam: A Catalyst for Cycloisomerization of Alkynoic Acids to gamma-Alkylidene Lactones

作者：Eriksson Kristofer; Verho Oscar; Nyholm Leif; Oscarsson Sven; Backvall Jan E^*

来源：European Journal of Organic Chemistry, 2015, 2015(10): 2250-2255.

DOI：10.1002/ejoc.201403664

• Cycloisomerization
• Alkynoic acids
• Nanoparticles
• Gold
• Heterogeneous catalysis

A versatile approach for the production of dispersed thiol-stabilized gold nanoparticles in the pores of siliceous mesocellular foam (MCF) is described. The reported method is based on an electrochemical oxidation of a gold surface generating oxidative Au-III species, which give rise to a surface-confined redox reaction yielding MCF-supported Au-I thiolates. By reducing the corresponding Au-I-S-MCF species with sodium borohydride, thiol-stabilized gold nanoparticles in the size range of 1-8 nm were obtained as determined by transmission electron microscopy. Elemental analysis indicated an Au loading of 3% (w/w) on the MCF. The surface-confined Au nanoparticles were used to catalyze the cycloisomerization of alkynoic acids to the corresponding -alkylidene lactones in high efficiency and complete 5-exo-dig selectivity under mild reaction conditions.

• 出版日期2015-4