Selective peroxygenase-catalysed oxidation of toluene derivatives to benzaldehydes

“Biocatalytic oxidation reactions of toluene derivates to the corresponding aldehydes are typically challenged by regio- and chemoselectivity issues. In this contribution we address both challenges by a combined reactant- and reaction engineering approach. We demonstrate that the peroxygenase-catalysed transformation of ring-substituted toluenes proceeds highly regioselectively in benzylic position. Furthermore, neat reaction conditions not only enable attractive product concentrations (up to 185 mM) but also result in highly chemoselective oxidations to the aldehyde level.”

Highlight:

• “For the scale-up reaction, model substrate p-Cl-toluene was used as starting material, and rotating bed reactor (RBR) was utilised to conduct the reaction. Specifically, the reaction was conducted in a SpinChem Vessel S2 (200 mL) using a SpinChem RBR S2 rotating bed (SpinChem AB, Sweden). The rotating bed was loaded with 18 g imm-AaeUPO, and the reactor was filled with 120 mL p-Cl-toluene. The rotating bed was adjusted to be 1 cm above the reactor bottom, and the reaction was run at 400 rpm and 30 °C. tBuOOH (600 mM in n-decane) was fed with syringe pump 2 mL.h-1.”