A Materials Approach to the Dual-Site Isolation of Catalysts Bonded to Linear Polymers and Small, Ionic Molecules for Use in One-Pot Cascade Reactions

摘要

The site-isolation of homogenous catalysts by bonding to a polymer support is a common motif in chemistry. Catalysts are typically bonded to polymers to aid in their separation from the products of a reaction such that they can be recycled. These catalysts allow for less waste in a reaction sequence and lower costs associated with catalysts that are often expensive and toxic. A recent advance was made in this field when Hawker and Frechet showed that star polymers with acidic and basic residues could be added to the same reaction vessel such that acid- and base-catalyzed reactions occurred at the same time. These star polymers were cross-linked nanoparticles with acidic and basic residues bonded to them that allowed steric crowding of the polymers to keep the catalysts from quenching each other. This work was a major advance because previously impossible cascade reactions -denned as two or more reactions occurring in one reaction vessel -could be accomplished.