Book excerpt: The construction of d3-methylated all-carbon quaternary stereocenters has been successfully developed via carbene-catalyzed desymmetrization of prochiral d3-methylated oxindolyl 1,3-diketones. Three new stereogenic centers were efficiently constructed with satisfactory outcomes. Diverse spiro-polycyclic molecules with a d3-methylated all-carbon quaternary stereocenter were generated in good to excellent yields with good to excellent diastereoselectivities and excellent enantioselectivities. This reaction features a broad substrate scope, good functional-group tolerance, and easy scale-up.