Bis(oxazoline) Iron Complexes Enable Tuning of Lewis Acidity for Catalytic Carbonyl–Olefin Metathesis

Carbonyl–olefin metathesis reactions are powerful
transformations
for carbon–carbon bond formation. Despite recent progress,
limitations exist that hamper the synthetic generality of the reported
approaches. Catalytic systems that will enable tuning of their Lewis
acidity and consequently the selective activation of specific substrate
classes are expected to greatly enhance the current scope. We herein
report the development of cationic iron-bis(oxazoline) complexes as
powerful catalysts that enable the alteration of Lewis acidity to
efficiently convert substrate types that were previously found to
be incompatible with existing catalytic systems in carbonyl–olefin
ring-closing metathesis.