We report herein that the Ir and Cu-I bis-metal catalyzed reductive alkynylation of amides, a method that we developed previously, can be extended to 6-, 7-, and 8-membered lactams. The catalytic reductive alkynylation of 6-methyl-2-piperidinones and its 3-benzyloxy derivative proceeded with 2.3:1 to 7:1 2,6-trans/cis diastereoselectivities. The resulting piperidines were converted into alkaloids (+/-)-solenopsin, (+/-)-solenopsin A, and (+)-julifloridine all in only one step. This two-step approach to the alkaloids is much shorter and much efficient than the conventional multistep methods.