Tandem catalysis is one of the strategies used by Nature for building macromolecules. Living organisms generally synthesize macromolecules by in vivoenzyme-catalyzed chain growth polymerization reactions using activated monomers that have been formed within cells during complex metabolic processes. In the same spirit, we initiate a research effort to synthesize polymers via tandem catalytic transformations. The objectives for this are clear: not only can a reduction in workload, waste and energy consumption be achieved, but also the synthesis of complex products that are otherwise difficult to obtain (e.g., because of thermodynamic hurdles) comes within reach. In other words, the combination of chemistries may allow the direct synthesis of macromolecules with high structural complexity. Developing a tandem catalytic system is a difficult task, which requires an effective ligand framework for achieving high activity and control during the polymerization reaction and stabilization of the metal centre towards the solvent, substrate, and reaction side products and preventing decomposition of the active species.
Key Words: One-Pot, Tandem, Catalysis
Tandem catalysis: a new approach to polypeptides and cyclic carbonates
A new tandem catalytic system mediates very efficiently and selectively at room temperature two sequential reactions to produce relevant derivatives in one pot. Remarkably, this new concept of catalysis allows the facile synthesis of polypeptides and provides direct access to cyclic carbonates in high yields, through the incorporation of the carbon dioxide released from the initial step, thus achieving full-atom economy.
Tandem catalysis: a new approach to polymers
The creation of polymers by tandem catalysis represents an exciting frontier in materials science. Tandem catalysis is one of the strategies used by Nature for building macromolecules. Living organisms generally synthesize macromolecules by in vivo enzyme-catalyzed chain growth polymerization reactions using activated monomers that have been formed within cells during complex metabolic processes. However, these biological processes rely on highly complex biocatalysts, thus limiting their industrial applications. In order to obtain polymers by tandem catalysis, homogeneous and enzyme catalysts have played a leading role in the last two decades. In the following feature article, we will describe selected published efforts to achieve these research goals.
Tandem synthesis of alternating polyesters from renewable resources
The vast majority of commodity materials are obtained from petrochemical feedstocks. These resources will plausibly be depleted within the next 100 years, and the peak in global oil production is estimated to occur within the next few decades. In this regard, biomass represents an abundant carbon-neutral renewable resource for the production of polymers. Here we report a new strategy, based on tandem catalysis, to obtain alternating polyesters from renewable materials. Commercially available complexes are found to be effi cient catalysts for the cyclization of dicarboxylic acids followed by alternating copolymerization of the resulting anhydrides with epoxides. This operationally simple method is an attractive strategy for the production of new biodegradable polyesters.