Bulk gold-catalyzed reactions of diazoalkanes with amines and O2 to give enamines

Article abstract of DOI:10.1007/s10562-010-0339-7

Bulk gold powder, consisting of approximately 5-50 μm particles, catalyzes reactions of diazoalkanes E(H)C=N₂, where E is CO ₂Et or PhC(O), with amines R¹R²NH and O ₂ to give enamine products (R¹R²N)(E)C=CH(E) in 58-94% yield. The reactions are proposed to occur by initial formation of surface-bound (E)(H)C: carbene groups that are attacked by nucleophilic amines. The enamine products are very different than those obtained in reactions catalyzed by homogeneous transition metal complexes. These reactions of diazoalkanes, amines, and O₂ represent a new type of bulk gold-catalyzed reaction.