Bulk gold powder, consisting of approximately 5-50 lm particles, catalyzes reactions of diazoalkanes E(H)C=N 2 , where E is CO 2 Et or PhC(O), with amines R 1 R 2 NH and O 2 to give enamine products (R 1 R 2 N) (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 O 2 represent a new type of bulk gold-catalyzed reaction.