Emerging Fields in One-pot Multi-step Synthesis with Combined Chemo- and Bio-catalysts: Sequential- and Domino-type Process Concepts as well as Compartmentation Strategies
The combination of chemo- and biocatalysts towards multi-step chemoenzymatic one-pot syntheses has recently gained increasing interest due to a range of benefits. By direct transformation of the formed intermediates without purification steps, a number of time-consuming process unit operations steps can be avoided and the overall amount of solvent consumption significantly reduced. A major challenge is to achieve compatibility of the different reaction types with each other, which often run preferably under different ‘process windows’. However, promising proof of concept work has demonstrated the suitability of combining chemo- and biocatalysts towards one-pot syntheses as an attractive process concept. In addition, several emerging fields in this research area have arisen, such as development of domino-type tandem reactions, in which chemo- and biocatalytic reactions proceed simultaneously, as well as development of solutions for one-pot processes under a combination of chemo- and biocatalysts that are incompatible with each other. A major concept being used for such cases is catalyst compartmentation within one reactor, and it is noteworthy that the size of such compartments can vary broadly from the molecular to the nano- and macroscopic scales. Synthetically attractive solutions have allowed chemoenzymatic one-pot processes based on following concepts (i) sequential-type one-pot multi-step processes, (ii) domino-type one-pot multi-step processes, and (iii) compartmentation of catalysts within either one reactor or multi-reactor systems.