<p></p><p></p><p>Switchable catalysis offers opportunities
to control the rate or selectivity of a reaction <i>via</i> a stimulus such as
pH or light. However, few examples of switchable catalytic systems that can
facilitate multiple processes exist. Here we report a rare example of such dual-functional,
switchable catalysis. Featuring an easily prepared, bench-stable cobalt(I)
hydride complex in conjunction with pinacolborane, we can completely alter the
reaction outcome between two widely employed transformations – olefin migration
and hydroboration – with visible light as the sole trigger. This dichotomy arises
from ligand photodissociation which leads to metamorphosis of the active
catalytic site, resulting in divergent mechanistic pathways.</p><p></p><p></p>
