Quantum　optical　methods　have　great　potential　for　highly　efficient　discrimination　of　chiral　molecules.　We　propose　quantum　interference-based　schemes　of　enantio-discrimination　under　microwave　regime　among　molecular　rotational　states.　The　quantum　interference　between　field-driven　one-　and　two-photon　transitions　of　two　higher　states　is　designed　to　be　constructive　for　one　enantiomer　but　destructive　for　the　other,　since　a　certain　transition　dipole　moment　can　be　set　to　change　sign　with　enantiomers.　Therefore,　two　enantiomers　can　evolve　into　entirely　different　states　from　the　same　ground　state.　Through　strengthening　the　constructive　interference,　the　quantum　Zeno　effect　is　found　in　one　enantiomer　and　then　its　excitation　is　suppressed,　which　also　enables　the　enantio-discrimination.　We　simulate　the　schemes　for　differentiating　between　S　and　R　enantiomers　of　1,　2-propanediol　(C3H8O2)　molecules.　With　the　analysis　of　the　phase　sensitivity　to　microwave　fields　and　the　effect　of　energy　relaxations,　the　highly　efficient　enantio-discrimination　of　the　1,　2-propanediol　molecules　may　be　achieved.　(C)　2020　Optical　Society　of　America　under　the　terms　of　the　OSA　Open　Access　Publishing　Agreement