• Biocatalytic Silylation: The Condensation of Phenols and Alcohols with Triethylsilanol

      Sparkes, Emily I.; email: emilysparkes11@gmail.com; Egedeuzu, Chisom S.; orcid: 0000-0002-1380-234X; email: chisom.egedeuzu@manchester.ac.uk; Lias, Billie; email: billie.lias@student.manchester.ac.uk; Sung, Rehana; email: rehana.sung@manchester.ac.uk; Caslin, Stephanie A.; email: stephanie.caslin@sky.com; Tabatabaei Dakhili, S. Yasin; email: s.yasin.tabatabaei.d@gmail.com; Taylor, Peter G.; email: peter.taylor@open.ac.uk; Quayle, Peter; email: Peter.Quayle@manchester.ac.uk; Wong, Lu Shin; orcid: 0000-0002-7437-123X; email: l.s.wong@manchester.ac.uk (MDPI, 2021-07-22)
      Silicatein-α (Silα), a hydrolytic enzyme derived from siliceous marine sponges, is one of the few enzymes in nature capable of catalysing the metathesis of silicon–oxygen bonds. It is therefore of interest as a possible biocatalyst for the synthesis of organosiloxanes. To further investigate the substrate scope of this enzyme, a series of condensation reactions with a variety of phenols and aliphatic alcohols were carried out. In general, it was observed that Silα demonstrated a preference for phenols, though the conversions were relatively modest in most cases. In the two pairs of chiral alcohols that were investigated, it was found that the enzyme displayed a preference for the silylation of the S-enantiomers. Additionally, the enzyme’s tolerance to a range of solvents was tested. Silα had the highest level of substrate conversion in the nonpolar solvents n-octane and toluene, although the inclusion of up to 20% of 1,4-dioxane was tolerated. These results suggest that Silα is a potential candidate for directed evolution toward future application as a robust and selective biocatalyst for organosiloxane chemistry.