Density functional theory has been applied to gain insight into the Cp*Rh(OAc)(2)-catalyzed CH activation and intermolecular annulation of benzamide derivatives with allenes. The study shows that the reactions proceed in three steps: (1) CH activation induced by Rh catalyst reacting with benzamide derivatives, (2) carborhodation of allene, and (3) regeneration of Rh catalyst. The results indicate that the NH deprotonation makes the following CH activation much easier. The regio- and stereoselectivities of 1a (N-pivaloyloxy benzamide)/2a (cyclohexylallene) and 1b (N-pivaloyloxy-4-methyl-benzamide)/2b (1,1-dimethyl allene) depend on the allene carborhodation step. The steric hindrance effect is the dominant factor. We also discuss the reaction mechanism of 1c (N-methoxy benzamide)/2a. The chemoselectivity between 1c/2a is determined by the NO cleavage step. Replacement of OPiv by OMe leads to loss of the stabilization effect provided by C-O in OPiv. Additionally, Cp*Rh(OAc)(OPiv) is produced in the Cp*Rh(OAc)(2) regeneration step, which can work as catalyst as well.