The Caulobacter segnis dioxygenase has been employed for the enzymatic alkene cleavage of several stilbenoids, thus generating the corresponding aldehydes. CsO2-mediated ozonolysis represents a greener, safer, and more selective process with respect to conventional chemistry. To further assess the CsO2 usability as a preparative biocatalyst, a 50–mL scale biotransformation of resveratrol has been carried out obtaining the corresponding aldehydes with excellent yields (98 %), rapid reaction times (1.5 h) and unprecedented substrate-to-catalyst ratio (5 103).
Ozonolysis is a useful as well as dangerous reaction for performing alkene cleavage. On the other hand, enzymes are considered a more sustainable and safer alternative. Among them, Caulobacter segnis dioxygenase (CsO2) known so far for its ability to catalyze the coenzyme-free oxidation of vinylguaiacol into vanillin, was selected and its substrate scope evaluated towards diverse natural and synthetic stilbenoids. Under optimized conditions, CsO2 catalyzed the oxidative cleavage of the C=C double bonds of various trans-stilbenes, providing that a hydroxyl moiety was necessary in para-position of the phenyl group (e. g., resveratrol and its derivatives) for the reaction to take place, which was confirmed by modelling studies. The reactions occurred rapidly (0.5–3 h) with high conversions (95–99 %) and without formation of by-products. The resveratrol biotransformation was carried out on 50–mL scale thus confirming the feasibility of the biocatalytic system as a preparative method.Zum Volltext