A new strategy for selective insertion of metal carbenes into C–N bond has been developed via Pd-catalyzed C–N bond activation. A series of aminals and α-diazoesters with different substituents were successfully incorporated even in 0.1 mol % of catalyst under mild conditions, affording a wide range of α,β-diamino acid esters with quarternary carbon-centers. Preliminary mechanistic studies uncovered that the unique electrophilic cyclopalladated species could easily react with diazoacetates to generate a Pd-carbenoid intermediate which was involved in the catalytic cycle.