A Pd(II)-catalyzed oxidative Wacker-type cyclization/dearomatization of 2,3-disubstituted indoles with molecular oxygen as the oxidant has been developed. This strategy provides straightforward access to diverse fused indolines bearing C2-oxygenated quaternary stereocenters with good functional group tolerance and high atom economy. Meanwhile, a Pd(II)-catalyzed oxidation/dearomatization of 2-substituted indoles is also presented, which enables the facile synthesis of indolones.