Institute of Chemistry, Department of Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed Graz, Heinrichstrasse 28, 8010, Graz, Austria.
Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg1, 14476, Potsdam, Germany.
Angew Chem Int Ed Engl. 2021 Mar 22;60(13):6965-6969. doi: 10.1002/anie.202100164. Epub 2021 Feb 26.
Controlling the selectivity of a chemical reaction with external stimuli is common in thermal processes, but rare in visible-light photocatalysis. Here we show that the redox potential of a carbon nitride photocatalyst (CN-OA-m) can be tuned by changing the irradiation wavelength to generate electron holes with different oxidation potentials. This tuning was the key to realizing photo-chemo-enzymatic cascades that give either the (S)- or the (R)-enantiomer of phenylethanol. In combination with an unspecific peroxygenase from Agrocybe aegerita, green light irradiation of CN-OA-m led to the enantioselective hydroxylation of ethylbenzene to (R)-1-phenylethanol (99 % ee). In contrast, blue light irradiation triggered the photocatalytic oxidation of ethylbenzene to acetophenone, which in turn was enantioselectively reduced with an alcohol dehydrogenase from Rhodococcus ruber to form (S)-1-phenylethanol (93 % ee).
用光激发调控化学反应的选择性在热反应中较为常见，但在可见光光催化中较为罕见。本文中，我们展示了通过改变辐照波长来调变氮化碳光催化剂（CN-OA-m）氧化还原电势，从而产生具有不同氧化电势的空穴。这种调变是实现光-化学-酶级联反应的关键，该反应可以得到苯乙醇的（S）-或（R）-对映体。结合来自田头菇的一种非特异性过氧化物酶，绿光辐照 CN-OA-m 可以选择性地将乙苯羟化生成（R）-1-苯乙醇（99%ee）。相比之下，蓝光辐照会触发乙苯的光催化氧化生成苯乙酮，后者再用来自粘红酵母的醇脱氢酶进行对映选择性还原，生成（S）-1-苯乙醇（93%ee）。
