  Molecular matter-wave interferometry enables novel strategies for
manipulating the internal mechanical motion of complex molecules. Here, we show
how chiral molecules can be prepared in a quantum superposition of two
enantiomers by far-field matter-wave diffraction and how the resulting
tunnelling dynamics can be observed. We determine the impact of ro-vibrational
phase averaging and propose a setup for sensing enantiomer-dependent forces,
parity-violating weak interactions, and environment-induced superselection of
handedness, as suggested to resolve Hund's paradox. Using ab-initio tunnelling
calculations, we identify [4]-helicene derivatives as promising candidates to
implement the proposal with state-of-the-art techniques. This work opens the
door for quantum sensing and metrology with chiral molecules.
