We have been studying alkene transformations based on the MHAT mechanism and have identified that the MHAT/RPC reaction condition can be used to generate a strong electrophilic intermediate (cationic alkylcobalt(IV) complex) by adding an oxidant. The focus was placed on intramolecular reactions affording cyclic molecules, because the cationic alkylcobalt(IV) complex is equivalent to the carbocation obtained by protonated alkenes. We also studied an asymmetric version of MHAT/RPC, which has been a challenging transformation; however, the number of highly enantioselective examples is still limited. Further developments are anticipated.