The novel methods for the cationic ring expansion of cyclic ketone adducts have been developed. Palladium(0) catalyzed ring expansion of vinyl oxaspirohexanes occurred smoothly in the presence of 1 equiv of p-nitrophenol in tetrahydrofuran, yielding the ring-expanded cyclopentanones in high yields via $\pi$-allylpalladium cationic species. On the other hand, trimethylsilyl ethers of 1-alkenyl-l-cycloalkanols readily rearrange to the ring expanded $\beta$-mercurio cycloalkanones via mercurinium ions and $\beta$-thallium cycloalkanones via thallium ions. For unsymmetrical substrates, the more substituted alkyl group migrates preferentially. $\alpha$-Methylenecycloalkanones were obtained in good yields by elimination of the $\beta$-mercurio or $\beta$-thallium moiety with bases. Also, $\beta$-mercuriocycloalkanines undergo further ring expansion involving free radical reactions in the course of demercuration with $Bu_3SnH$ in methylene chloride. As a synthetic utility, hexahydro-1(2H)-anthracenone was produced via cationic ring expansion and intramolecular nucleophilic participation of a phenyl ring.