Aerobic oxidation of amines to imines catalyzed by bulk gold powder and by alumina-supported gold

Both bulk gold powder (similar to 50 mu m particle size) and alumina-supported gold (50-150 nm) are highly active catalysts for the aerobic oxidative dehydrogenation of amines (CH-NH) to imines (C=N) under the mild conditions of 1 atm O-2 and 100 degrees C. Reactions using the 5% Au/Al2O3 catalyst make efficient use of the gold metal and offer a practical synthesis of imines from amines. These studies add to the growing list of reactions that are catalyzed by bulk gold metal. (C) 2008 Elsevier Inc. All rights reserved.