  Molecular chirality is a key design property for many technologies including
bioresponsive imaging, circularly polarized light detection and emission,
molecular motors and switches. Imaging and manipulating the primary steps of
transient chirality is therefore central for controlling numerous physical,
chemical and biological properties that arise from chiral molecules in response
to external stimuli. So far, the manifestation of electron-driven chiral
dynamics in neutral molecules has not been demonstrated at their intrinsic
timescale. Here, we use time-resolved photoelectron circular dichroism
(TR-PECD) with an unprecedented instrument response function of 2.9 fs to image
the dynamics of coherent electronic motion activated by prompt UV-excitation in
neutral chiral molecules, disclosing its impact on the molecular chiral
response. We find that electronic beatings between Rydberg states lead to
periodic modulations of the chiroptical response on the few-femtosecond
timescale, showing a sign inversion in less than 10 fs. Calculations including
both the molecular UV-excitation and subsequent photoionization confirm this
interpretation and provide further evidence that the combination of the
resulting photoinduced chiral current with a circularly polarized probe pulse
realizes an enantio-selective filter of molecular orientations upon
photoionization, opening up a route towards enantio-selective charge-directed
reactivity.
