Rotaxane-structure-specific Pd-catalyzed rearrangement of propargyl or allyl urethane groups to oxazolidinone moieties proceeded efficiently. The conversion took place successively by the translation of the wheel along the axle, thus providing a novel macrocyclic catalytic system.
Palladium-containing macrocycle catalysts (PdMCs) with different ring sizes ranging from 24 to 30 members were synthesized. The intramolecular hydroamination of an allylurethane (AU) catalyzed by PdMCs proceeded efficiently to afford the corresponding oxazolidinone (OZ) in 95% isolated yield. The dependence of the hydroamination of AU to OZ on the cavity size indicated that the reaction rate was clearly controlled by both substrate uptake and product release steps.
Efficient Transformation of Polymer Main Chain Catalyzed by Macrocycle Metal Complexes via Pseudorotaxane Intermediate
Post-synthesis modification of polymers streamlines the synthesis of functionalized polymers, but is often incomplete due to the negative polymer effect. Here, we show macrocycle-metal-complex-catalyzed systems for efficient transformation of main chain in polymer substrate, whereby higher-molecular-weight polymers reach completion faster. Mechanistic studies suggest the reactions proceed via the formation