A novel method for direct transformation of allyl groups in allylbenzene derivatives to alkenyl groups via rhodium-catalyzed C-C bond cleavage is reported. The alkenylation with styrenes of allylbenzenes containing pyridyl and pyrazolyl groups as a directing group proceeded efficiently to give alkenylation products. We also developed a new protocol for transformation of an ortho-prenylated phenol to an aniline derivative.