An efficient iridium-catalyzedhydrogenation of 4,6-disubstituted 2-hydroxypyrimidines has been achieved, giving chiral cyclic ureas with excellent diastereoselectivities and up to 96% ee of enantioselectivities. In the presence of the in situ generated hydrogen halide, the equilibrium of the lactame–lactime tautomerism of 2-hydroxypyrimidine is more toward the oxo form with lower aromaticity, which