Investigating silicatein selectivity and specificity in silicon–oxygen bond condensation and metathesis†

Silyl ethers are an important group of compounds containing Si–O bonds with a variety of applications, but their formation currently relies on reagents that are undesirable from a sustainability perspective. This study is a further investigation of the biocatalytic silylation of alcohols using silanols or silyl ethers as the silyl donor, with the recombinant enzyme silicatein-α as the catalyst. It was found that the model enzyme-catalysed reactions gave better conversion of phenol to its corresponding phenoxy silane compared to the aliphatic n-octanol. The enzyme was selective for phenols and did not catalyse disiloxane formation. In addition, it was observed that the optimum temperature for the enzymatic conversion was 75 °C. The enzyme also showed superior catalysis compared to conventional small molecule base catalysts such as imidazole and triethylamine.