Selective Activation of C−H Bonds in a Cascade Process Combining Photochemistry and Biocatalysis

• Published in: Angewandte Chemie International Edition Vol. 56; no. 48; pp. 15451 - 15455
• Main Authors: Zhang, Wuyuan, Burek, Bastien O., Fernández‐Fueyo, Elena, Alcalde, Miguel, Bloh, Jonathan Z., Hollmann, Frank
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 27.11.2017; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Activation; Biocatalysis; Carbon - chemistry; Catalysis; Communication; Communications; Enantiomers; Ethylbenzene; Gold; Gold - chemistry; Gold - metabolism; Hydrogen - chemistry; Hydrogen peroxide; Hydrogen Peroxide - chemistry; Hydrogen Peroxide - metabolism; Hydroxylation; Mixed Function Oxygenases - chemistry; Mixed Function Oxygenases - metabolism; Molecular Structure; oxyfunctionalization; peroxygenases; photocatalysis; Photochemical Processes; Photochemistry; Stereoisomerism; TiO2; Titanium - chemistry; Titanium - metabolism; Titanium dioxide; Biocatalysis; photocatalysis; TiO2; oxyfunctionalization; peroxygenases
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201708668

Selective oxyfunctionalizations of inert C−H bonds can be achieved under mild conditions by using peroxygenases. This approach, however, suffers from the poor robustness of these enzymes in the presence of hydrogen peroxide as the stoichiometric oxidant. Herein, we demonstrate that inorganic photocatalysts such as gold–titanium dioxide efficiently provide H2O2 through the methanol‐driven reductive activation of ambient oxygen in amounts that ensure that the enzyme remains highly active and stable. Using this approach, the stereoselective hydroxylation of ethylbenzene to (R)‐1‐phenylethanol was achieved with high enantioselectivity (>98 % ee) and excellent turnover numbers for the biocatalyst (>71 000). Inorganic photocatalysis with Au‐TiO2 and selective enzymatic catalysis were combined for the oxyfunctionalization of inert C−H bonds. The hydroxylation of ethylbenzene to (R)‐1‐phenylethanol was thus achieved with high enantioselectivity and excellent turnover numbers.