Biocatalysis in Silicon Chemistry

Abstract

The application of biocatalytic or chemoenzymatic techniquesi ns ilicon chemistry serves two roles:i tp rovides ag reater understanding of the processing of silicon species by natural systems, such as plants, diatoms, and sponges, as well openingu pa venues to green methodologies in the field. In the latter case, biocatalytic approaches have been applied to the synthesis of small-molecule systems and polymeric materials. Often these biocatalytic approaches allow access to molecular structures under mild conditions and, in some cases, molecular structures that are not accessible throught raditional chemical methodologies. Ar eview of recent advances in the applications of biocatalysis in silicon chemistry is presented.

Selective Enzymatic Oxidation of Silanes to Silanols

“…Even though silicon is the second most abundant element in the Earth's crust, the silicon chemistry of the biological world is very limited. Diatoms, for example, can incorporate ortho ‐silicic acid as stabilizing units in skeletons and materials; this process is usually based on the hydrolysis or alcoholysis of Si−O bonds . Biocatalytic approaches for the formation of silicon polymers and small molecules are so far limited to the formation of Si−OR bonds through condensation reactions .…”

“…Diatoms, for example, can incorporate ortho ‐silicic acid as stabilizing units in skeletons and materials; this process is usually based on the hydrolysis or alcoholysis of Si−O bonds . Biocatalytic approaches for the formation of silicon polymers and small molecules are so far limited to the formation of Si−OR bonds through condensation reactions . Although enzymatic manipulations of functional groups in the neighborhood of or remote to the silicon in various organosilicon compounds have been reported, the direct biocatalytic functionalization of silicon centers remained unknown until this group engineered a cytochrome c enzyme in 2016 to catalyze carbene insertion into Si−H bonds in vitro and in vivo .…”

Biocatalytic Transformations of Silicon—the Other Group 14 Element

“… 39 , 40 Most of these reactions were developed for the enantioselective reduction of silicon compounds and have been summarized in detail in excellent reviews by Frampton and Zelisko. 41 , 42 …”

Expanding beyond canonical metabolism: Interfacing alternative elements, synthetic biology, and metabolic engineering

“…To this end, microorganisms capable of producing a variety of precursor molecules have the potential to be expanded in their use to include rare-element analogues which can be further utilized in downstream chemical applications [3] . Such transformations include small molecules containing silicon and halogens, for example, that are suitable for reactions like cross-couplings [23] , electrophilic cleavage [24] , and polymerizations [25] . These efforts involve both protein engineering and synthetic biology along with metabolic engineering to expand the chemical reach of cellular metabolism.…”

“…Other organisms, including Pichia pijperi , have shown to be more efficient at reducing these and expression of toluene dioxygenase in E. coli results in the dioxygenation of several phenyl silanes [118] . Free enzymes in non-aqueous solvents can perform more complex reactions such as polymerizations and generation of siloxane-phospholipids, but these conditions are not immediately compatible with in vivo use [24] .…”