With the increasing demand for homoallylic silanes and allylic silanes,
the highly efficient and regioselective hydrosilylations of conjugated
dienes are urgently needed. Herein, we developed a Ni-catalyzed
regiodivergent hydrosilylation of aromatic conjugated dienes by
adjusting the temperature and ligands. Under low temperature (-30
oC), an eternal-ligand-free system (Ni/t-BuOK)
can efficiently facilitate the 3,4-anti-Markovnikov
hydrosilylation to provide homoallylic silanes via electrophilic
activation process; under room temperature (25 oC), a
ligand-controlled system (Ni/t-BuOK/PPh3) can
eventuate the 3,4-Markovnikov hydrosilylation to produce allylic silanes
via Chalk-Harrod process. Both systems are compatible with
various conjugated dienes and primary silanes in excellent yields and
regioselectivities. |