Effect of Tethered, Axially Coordinated Ligands (TACLs) on Dirhodium(II,II) Catalyzed Cyclopropanation: A Linear Free Energy Relationship Study
Cristian Zavala, Ampofo Darko
Abstract
Hammett correlation experiments were used to determine the influence of dirhodium(II,II) paddlewheel complexes with tethered, axially coordinated ligands (TACLs) on the selectivity of rhodium carbenoids in competitive cyclopropanation reactions. The results suggest that dirhodium(II,II) paddlewheel complexes with TACLs are less sensitive to changes in electronics and reduce selectivity in cyclopropanation reactions with acceptor-substituted rhodium carbenoids. Also, Hammett plots with aryl diazoacetates resulted in a nonlinear downward curvature, suggesting a change in the rate-limiting step of the carbene transfer reaction.
Topics & Concepts
CyclopropanationChemistryRhodiumCarbeneSelectivityArylCatalysisFree-energy relationshipMedicinal chemistryDiazoAcceptorPhotochemistryStereochemistryOrganic chemistryReaction rate constantKineticsAlkylQuantum mechanicsCondensed matter physicsPhysicsCyclopropane Reaction MechanismsSynthesis and Catalytic ReactionsCatalytic C–H Functionalization Methods