A novel and efficient entrance to the pyrimidine skeleton has been presented via the α,β-dehydrogenation and deamination of tertiary alkylamines. This I2-catalyzed dehydrogenative multicomponent procedure utilizes simple aldehydes to trap the hidden enamine intermediates and suspend generation of azadienes from amidines, enabling the difunctionalization of a vicinal C(sp3)-H bond. These studies provide valuable possibilities for the introduction of aliphatic substituents and show how to switch to a new reactive modality.